B1049 was the oldest Falcon 9 booster on active duty until its last flight on Nov 22, 2022, after which this title went to B1052. It was the first to successfully launch and land six, then seven times, and the second to launch and land eight, nine, and then ten times respectively. It launched two commercial payloads, Telstar 18V and the eighth Iridium NEXT batch, and eight internal Starlink batches.[265] B1049 was seen with its landing legs and grid fins removed indicating that it would be expended on its next flight. The final flight of B1049 was originally thought to be O3b mPower 4-6 but a regrouping of the launches meant that an expendable booster was no longer required. It was then planned that B1049's last flight would be the launch of Nilesat-301 however, those plans changed and the mission was flown with a recoverable booster (B1062.7). B1049 flew the Eutelsat-10B communications satellite with a Test/Spare Block 4 interstage on November 22, 2022. This mission was its last flight.[82][102][266]

This timeline displays all launches of Falcon 9 boosters starting with the first launch of Full Thrust. Active boosters that are expected to make additional flights in the future are marked with an asterisk. Single flights are marked with vertical lines. A short white gap indicates conversion between Falcon 9 and Falcon Heavy side formats. For boosters having performed several launches, colored bars indicate the turnaround time for each flight.

B1060Suzuki

In 2022, the Falcon 9 set a new record with 60 successful launches by the same launch vehicle type in a calendar year. This surpassed the previous record held by Soyuz-U, which had 47 launches (45 successful) in 1979.[233] In 2023, the Falcon family of rockets (including the Falcon Heavy) had 96 successful launches, surpassing the 63 launches (61 successful) of the R-7 rocket family in 1980.[a][234]

B1060reddit

In our clinical practice, XLPE liners with ceramic heads are the first option in older patients, or in younger patients when a reliable correct positioning of the acetabular component cannot be obtained intra-operatively due to anatomical abnormalities.

Nowadays the most commonly used ceramic is the alumina matrix composite (AMC) (Biolox Delta; CeramTech AG, Plochingen, Germany). In 2016, AMC accounted for 92.0% of all procedures with CoC bearing surface in the Australian Registry.5 AMC, introduced in the early 2000s, is the fourth generation of Biolox Ceramics, composed of 82% alumina and 17% zirconia, with the addition of chromium oxide (0.5%) to enhance hardness and strontium crystals (0.5%) to diffuse crack energy. This material has a smaller grain size (< 0.8 µm) compared with previous ceramics, and was developed in order to reduce the risk of implant fractures. In the last few years mid- to long-term follow-up studies of AMC have been published, with a ten-year survival rate from 98% to 99.3% at two to ten years.55 These excellent results are confirmed by registry data: the Australian Registry reports a CoC survival of 92.8% at 15 years.5

Total hip arthroplasty (THA) is widely considered to be one of the most successful surgical procedures in orthopaedics. It is associated with high satisfaction rates and significant improvement in quality of life following surgery.1,2 According to recently published data from the British National Joint Registry, the cumulative survival of THA at 13 years is 93.2%, with 80% of implants surviving up to 20 years.3,4 Moreover, the number of THAs performed worldwide is increasing. According to the Australian Arthroplasty Registry, there was an increase of 5.5% between 2015 and 2016, and an increase of 109.7% between 2003 and 2016 in that country.5 In Italy, between 2001 and 2015, there was an annual increase rate of 2.5% for THA performed.6

Because of the influence that the discussed elements have on in vivo performance of the PE liners, the surgeon must be aware of the chosen liner characteristics concerning sterilization and production processes, in order to choose the optimal one for each patient.

The science that studies friction, lubrication and wear between two surfaces which are in close contact and move one on the other. The name is derived from the Greek word ‘Τριβος,’ which means rubbing.

SpaceX decided not to fly the booster again.[243] Rather, the rocket was moved a few miles north, refurbished by SpaceX at the adjacent Kennedy Space Center, to conduct a static fire test. This test aimed to assess the health of the recovered booster and the capability of this rocket design to fly repeatedly in the future.[244][240] The historic booster is on display outside SpaceX headquarters in Hawthorne, California.

Very few studies have directly compared the various combinations of bearings at long-term follow-up. Randomized controlled trials show similar short- to mid-term survivorship among the best performing bearing surfaces (CoC, CoXLPE and MoXLPE). Selection of the bearing surface is often ‘experience-based’ rather than ‘evidence-based’.

For the aforesaid risks linked to malposition and soft-tissue balancing, the use of CoC has a possible contra-indication in our practice in young patients, in the few cases when it can be difficult to reach the correct orientation of the acetabular component and off-set, such as severe developmental dysplasia of the hip or post-traumatic acetabular deformity. Patients showing weakness of the pelvic muscles, soft-tissue laxity or excessive range of movement should also be considered at risk.70 In our clinical practice, CoC is the bearing of choice in younger and more active patients.

The Falcon Heavy derivative is a heavy-lift launch vehicle composed of three Falcon 9 first-stage boosters. The central core is reinforced, while the side boosters feature aerodynamic nosecone instead of the usual interstage.[236]

In conclusion, a comprehensive knowledge of the characteristics, advantages and drawbacks of each bearing surface is essential for surgeons who routinely perform THA. This, along with personal experience, will help in selecting the best coupling for each patient in order to provide the best long-term survivorship of the prosthesis. In our experience, CoC in young and active patients (for the higher wear resistance and biocompatibility) is a good option. CoXLPE and MoXLPE are a valid option for ‘older’ patients (more ‘forgiving’ bearings, and good results are reported at 15 years). Moreover, surgeons must remember that what makes the difference is not just the material, but the correct surgical technique and handling of the components – mainly the positioning of the implant.

Relative low amplitude movement (oscillation and sliding) between two mechanically joined parts, under load conditions (between 1 µm and 100 µm). All modular junctions are susceptible to the loading of the body. It provokes wear (debris) and corrosion.

Falcon 9 B1058 was first launched on 30 May 2020, from Kennedy Space Center Launch Complex 39A (Apollo 11 launch site). It carried NASA astronauts Doug Hurley and Bob Behnken to the International Space Station. It was the first crewed orbital spaceflight launched from the United States since the final Space Shuttle mission, and the first crewed flight test of Dragon 2. It was the first crewed orbital spaceflight by a private company. The booster was the first and only Falcon 9 booster to feature NASA's worm logo and meatball insignia, which was reintroduced after last being used in 1992.[274]

This approach is reflected by trends and usage percentages of bearing surfaces in major geographical areas: in the United States the use of ceramic heads increased between 2012 and 2016, while the use of metal heads decreased (60% metal and 36.8% ceramic in 2012, to 42.6% metal and 52.8% ceramic in 2016).18 In Italy, the only available data refer to a single region, Emilia-Romagna: between 2001 and 2013 a steep increase in CoC coupling was observed (20.5% compared with 62.1%), associated with a decrease in metal head usage (41.2% to 10.3%).19 Conversely, in the United Kingdom, since the decline in usage of MoM bearings in 2010, an increase in CoP has been observed (12.2% in 2010 to 32.7% in 2016; data refer to uncemented prostheses), with a decrease in CoC (39.5% to 24.9%), while MoP couplings remained constant.3 These data highlight a substantial difference in trends and overall percentage of selection of various bearings.

THA is overall a very successful procedure. The long-term survival and satisfaction of patients is linked to the proper bearing surface selection. The surgeon has a responsibility to make a wise choice, based on a comprehensive knowledge of the features of the selected bearing.

While THA is a successful procedure in most cases, failures are still recorded. Overall, excluding metal-on-metal (MoM) bearings from the analysis, failures due to articulating materials represent around 5% of the total number of implants.3,5 When considering only late failures, defined as the ones occurring after ten years or more, osteolysis and implant wear become the most common causes for revision when associated with aseptic loosening.7,8

B1046 was the first Block 5, the final version of the SpaceX Falcon 9. It was first launched on 11 May 2018, carrying Bangabandhu-1, Bangladesh's first geostationary communications satellite. This marked the 54th flight of the Falcon 9 and the first flight of the Falcon 9 Block 5.[259] After completing a successful ascent, B1046 landed on the drone ship Of Course I Still Love You. After inspection and refurbishment, B1046 was launched a second time on 7 August 2018, carrying the Telkom-4 (Merah Putih) satellite. The Telkom-4 mission marked the first time an orbital-class rocket booster launched two GTO missions. This was also the first re-flight of a Block 5 booster.[260] Four months after the Telkom-4 mission, B1046 arrived at Vandenberg Air Force Base to support the SSO-A mission. Following delays for additional satellite checks,[261] liftoff occurred from SLC-4E on 3 December 2018. This marked the first time that the same orbital-class booster flew three times.[262] Its fourth and last mission launched a Crew Dragon capsule up to the point of maximum dynamic pressure, where it separated from the rocket to test its abort system in flight to validate the system's safety for crews. After separation of Falcon and Dragon, B1046 was compromised by aerodynamic forces.

B1060 first flew on 30 June 2020, a month after Demo-2. Further missions it supported include launches of Starlink v1, v1.5 and v2 Mini, two Transporter ridesharing missions, and three large commercial satellites. After becoming the senior active rocket for SpaceX on 25 December 2023, it was assigned to what would become the first successful commercial Lunar landing: the booster launched IM-1 on 15 February 2024. This was its eighteenth mission.[279]

SpaceX attempted parachute of the Falcon 9 v1.0 first stage on flights 1 and 2, however on both attempts the boosters disintegrated on re-entry, and the plans were abandoned in favor of propulsive landings. Boosters B0002 (Grasshopper) and B1002 (F9R Dev1) were modified to make short propulsive hops at test sites to demonstrate landing technologies, and were not used on orbital missions. Three boosters successfully made soft ocean touchdowns on orbital flights but were not recovered.

Falcon 9 B1019 was the first Full Thrust booster, and was first launched on 22 December 2015 for Falcon 9 flight 20 and landed on the Landing Zone 1 (LZ‑1) at Cape Canaveral. It became the first orbital-class rocket booster to perform a successful return to launch site and vertical landing.[240][241][242]

B1060spacex

Concerning the choice of femoral head, few data are available, with only small series and at short follow-up intervals41,42 and no long-term follow-up RCTs directly comparing metal versus ceramic heads coupled with XLPE.16 In a recent study by Cafri et al,37 based on a systematic analysis of registry data, an overall equal long-term performance was found between metal and ceramic heads. Data from the Australian registry suggested a lower revision rate of CoXLPE when compared with MoXLPE.5 Theoretical advantages of the ceramic compared with the metal heads are: the higher hardness with less risk of damage during implantation, the surface finishing with only negative peaks due to grains detachment rather than deformation, and the higher wettability thus producing a better lubrication of ceramic which can lead to less friction and scratching and theoretically less liner wear.43 Moreover, alumina does not induce biological intolerance and it is considered to be the material with the best biocompatibility. On the other hand, several recent studies reported the occurrence of adverse local tissue reactions to metal debris with the use of a metal head coupled with PE liners, due to trunnionosis at the head/neck junction.44-48 Patients developed soft-tissue damage, pseudotumours, osteolysis and had higher blood metal ions levels. This occurrence is due to fretting at the taper/head junction, and was reported with implants of different manufacturers. In a retrieval study by Kurtz et al,49 the fretting and corrosion at the taper/head junction were evaluated either with ceramic and metal heads. Ceramic heads showed significantly less fretting and corrosion, independent of the stem alloy used for the testing. Trunnionosis at the metal head-neck junction is a possible cause of painful THA that needs to be excluded after ruling out other causes of failure such as infection, but at the moment the feeling is that it could be a somewhat overestimated event. No one knows the real incidence of this phenomenon on a large scale and further research is needed.

B1058, first launched on 30 May 2020 (Crew Dragon Demo-2), was the only booster with NASA logos. On 11 September 2022, during a Starlink mission, it became the first to complete fourteen launches and landings to become the fleet leader. With another 5 Starlink missions, B1058 achieved 15, 16, 17, 18 & 19 launches and landings, the first to do so. B1062 had been the first to achieve 20th, 21st, 22nd and 23rd launches and landings of a booster. Guinness World Records holder B1067 is the current fleet leader after completing 24th launch and landings, the first to do so.[87] Amongst all B5 boosters, B1058 holds the record for most spacecraft (869) launched to orbit and while the record for most spacecraft mass launched to orbit by a single booster is held by B1062 (313,000 kg (690,000 lb)). B1063 is currently the oldest surviving booster in the Falcon 9 fleet.

Despite the successful landing in its nineteenth flight, the booster tipped over during transit due to rough seas and high winds. SpaceX has already equipped newer Falcon boosters with upgraded landing legs that have the capability to self-level and mitigate this type of issue.[278]

Falcon 9 Full Thrust (version 1.2 / Block 3) was the first version of the Falcon 9 to successfully land. Changes included a larger fuel tank, uprated engines and supercooled propellant and oxidizer to increase performance. Block 3 and Block 4 are found in this list while the active Block 5 is listed separately. Block 4 was a test version that included new hardware like titanium grid fins later carried over to the current Block 5. Flights of all Falcon 9 rockets up to Block 4 were limited to 2 flights only, with a total of 14 second flights of these variants. The boosters were either retired or expended after that second launch.

This article is distributed under the terms of the Creative Commons Attribution-Non Commercial 4.0 International (CC BY-NC 4.0) licence (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed.

Grasshopper consisted of "a Falcon 9 first-stage tank, a single Merlin-1D engine" with a height of 32 m (105 ft).[237] The booster used for Grasshopper had the serial number 0002.

B1019 SpaceX

The aim of this paper is therefore to evaluate the main advantages and drawbacks of various types of tribology in THA, while providing practical suggestions for the surgeon on the most suitable bearing surface option for each patient.

The pathophysiological mechanisms of polyethylene wear-induced osteolysis have been extensively studied.9-12 It has been shown that debris particles can induce a cellular response in periprosthetic tissues, with the up-regulation of toll-like receptors (TLRs) on macrophages. TLR signaling leads to up-regulation of many chemokines and cytokines, such as TNF-α, IL-1β, MCP1 and others. The inflammatory response that ensues leads to the activation of osteoclasts and induction of local bone resorption.

Falcon 9 B1021 was the first booster to be re-flown and the first to land on a droneship. It was first launched on 8 April 2016 carrying a Dragon spacecraft and Bigelow Expandable Activity Module (BEAM) on the SpaceX CRS-8 mission and landed on an autonomous spaceport drone ship (ASDS). After recovery, inspections and refurbishing, it was launched again on 30 March 2017 for the SES-10 mission and recovered successfully a second time. This event marks a milestone in SpaceX's drive to develop reusable rockets and reduce launch costs.[28][245][246][247][248] Following the second flight, SpaceX stated that they plan to retire this booster and donate it to Cape Canaveral for public display.[249][250] It was later put on public display outside Dish Network's headquarters in Littleton, Colorado in October 2023.[30]

When compared with XLPE, CoC bearings have some advantages worth noting. The first advantage is the very low friction and very low wear rates. This is due to the hardness and high wettability of the surface, as mentioned above, of the ceramic heads. Moreover, the few wear particles generated by ceramic components induce a less intense biological reaction compared with polyethylene debris. Histological analysis of long-term retrievals indeed found wear debris in individual macrophages, but the inertness of such debris does not trigger the granulomatous reaction necessary to induce osteolysis. A second advantage of CoC bearings is that wear is not directly dependent on the head diameter. This allows the surgeon to select a larger diameter head with fewer concerns compared with PE liners. The AMC liner can also be thinner (3 mm to 4 mm) compared with XLPE ones. Registry data3 show that when using a CoC coupling, larger diameter heads (36 mm) have significantly better survival rates at 14-year follow-up when compared with smaller heads (32 mm), while 28 mm heads have the highest revision rate, mainly in the first years after surgery. The 40 mm heads have a good survival, similar to 36 mm, but the follow-up is still too short, suggesting that these results should be interpreted with caution. These observations could be explained by a reduced risk of dislocation with the use of larger heads.

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Block 5 is the latest iteration of the Falcon 9 and Falcon Heavy boosters. Changes include a stronger heat shield, upgraded engines, new carbon composite sections (landing legs, engine sections, raceways, RCS thrusters and interstage), retractable landing legs, titanium grid fins, and other additions that simplify refurbishment and allow for easier reusability.[citation needed]

This chart lists how often boosters were flown. It is limited to the Full Thrust versions as previous versions were never recovered intact. The entries for Block 5 include active boosters that can make additional flights in the future. Blocks 1–3 made 27 flights with 18 boosters (1.5 flights per booster), Block 4 made 12 flights with 7 boosters (1.7 flights per booster). As of 17 December 2024, Block 5 made 358 flights with 30 boosters (11.9 flights per booster) with Falcon 9.

The second disadvantage of CoC bearings can be the occurrence of noises such as squeaking. Similar to ceramic liner fractures, there is a great variety of incidence (from 0% to 35%) among different metal back manufacturers reported in the literature.62,63 Several risk factors have been identified, such as age, obesity, activity level and acetabular component positioning.64-66 The perception of European surgeons is generally that this event is overestimated by colleagues practising outside Europe. In our clinical practice, we notice frequent cases of post-operative noises caused by the separation of the head from the liner due to post-operative soft-tissue laxity, such as clicking, knocking, popping and snapping, that resolve spontaneously in a few weeks, with only a few occasional typical squeakers. In these cases, the noise is caused by the friction of the components. The retrievals show ceramic grains detached from the head and the liner, which means dulling of the surface, edge-loading and wear (45 times greater than silent retrievals).67,68 The occurrence of a new delayed noise in a ceramic joint, particularly if linked to pain and malposition, must be carefully considered as it can be caused by breakage and wear of the ceramics that do not normally improve.69 Nonetheless, the phenomenon has a multifactorial origin, sometimes with conflicting features from published studies. The outcome and patient satisfaction are not affected.

On 11 September 2022, it flew for the 14th time and became the first booster to be recovered 14 times.[275] On 17 December 2022, it was also the first booster to fly and land for the 15th time.[276] On 10 July 2023, it broke the reusability record of flying and landing an orbital-class rocket booster for the 16th time and later went on to be the first to complete 17, 18, and 19 launches in the same year.[277]

Based on the above-mentioned concepts and departmental experience, our choice of indication regarding the articulation in primary standard cases of THA has not changed since 2004. It is:

Bone resorption due to biological response to debris including osteoclast activation that can compromise the bone stock around the implant and lead to loosening of the prosthesis in the advanced phase.

The other option among the best performing bearing surfaces is CoC. The first ceramic acetabular components were introduced in the 1970s by Pierre Boutin in France as cemented liners and in 1974 by Heinz Mittelmeier in Germany as cementless threaded liners and skirted heads. However, this generation of ceramics was characterized by a high rate of aseptic loosening and failure due to the poor fixation of both cemented and cementless implants, inadequate designs such as the bulky skirted heads and the strength problems due to the grain size of the first generation of alumina. Modern ceramic acetabular components featured titanium shells with rough surface finishing in which a ceramic liner is located while in the 1990s the alumina further improved to a higher purity grade with more uniform and smaller grains. This type of implant has a large number of long-term follow-up studies, with good to excellent clinical results.52-54

Total hip arthroplasty (THA) is widely considered one of the most successful surgical procedures in orthopaedics. It is associated with high satisfaction rates and significant improvements in quality of life following surgery. On the other hand, the main cause of late revision is osteolysis and wear, often a result of failure of bearing surfaces.

Falcon 9 B1069 launched SpaceX CRS-24 to ISS in December 2021 for NASA. SpaceX achieved the feat of 100 successful orbital rocket booster landings in this mission, coinciding with the sixth anniversary of its first booster landing. The rough seas led to the Octagrabber robot not being able to secure the booster to the deck, leading to both the booster, droneship and the Octagrabber robot being heavily damaged in transit.[285] It took months for SpaceX to refurbish B1069, returning into service only on Group 4-23 mission in August 2022.

Falcon 9 B1061 first launched Crew-1 to the ISS on 16 November 2020, the first operational flight of Crew Dragon, and landed on a drone ship.[280] It became the first booster to fly crew twice as well as the first reused booster to fly crew as a part of the Crew-2 mission.[281] This first stage went on to complete additional missions.[168] B1061 is the only booster to land on all of SpaceX's different landing zones and drone ships (not including LZ-2). It was expended on the ESA Hera launch on 7 October 2024. Booster 1061 flew a total of 23 flights, making it tied with B1062 for the oldest Falcon 9 booster.

Block 5 boosters were initially certified for 10 launches[83] which was increased to 15. A "deep-dive" examination has been performed on Falcon 9 B1058 and B1060 after their 15th flight,[84] and SpaceX certified Falcon 9 boosters for 20 missions. SpaceX has further increased the Falcon re-flight certification to 40 flights per booster, since 20 flights of some boosters are reached.[85][86]

On its next flight for Eutelsat Hotbird 13F, B1069 included a hosted promotional payload by FIFA, that was a box powered by Starlink containing two Adidas Al Rihla (the Journey) balls, that were to be used in 2022 FIFA World Cup in Qatar.[286] These match balls were launched and brought back by landing on the drone-ship surviving the stresses of re-entry. Later, they were taken out and shipped back to Qatar for the World Cup. This was the first payload on a Falcon 9 booster itself and demonstrated the reusability.[287] The balls' flight by SpaceX was, in part, a promotion for the company's Starlink satellite internet service. An associated website invited World Cup attendees to visit the Starlink office in Doha.[288]

B1058 SpaceX

The surgeon must keep in mind that not all XLPEs are the same, considering that aside from irradiation, melting technique and annealing can also influence the in vivo proprieties of XLPE. XLPE liners annealed after irradiation and below the melting temperature usually show good wear and fatigue performances but poor oxidation resistance; this happens because this process fails to neutralize all free radicals. On the other hand, XLPE liners re-melted after irradiation show good oxidation resistance but less fatigue resistance.28

Ceramicized metal (Oxynium)/XLPE is the bearing surface with the highest survival at ten years in the Australian Registry,5 but the Registry report advice is to interpret this result with caution. The reason is that this is a single company product, used with a small number of cases. This may have a confounding effect on the outcome, compared with the other bearing surfaces used in many different combinations.

below the age of 60 years: CoC (32 mm or 36 mm depending on the acetabular component size and on the metal back thickness; 40 mm is selected nowadays only in cases of large acetabula at higher risk of dislocation in the middle-aged population but not in very young patients);

All boosters in Block 4 and earlier have been retired, expended, or lost. The last flight of a Block 4 booster was in June 2018. Since then all boosters in the active fleet are Block 5.

When considering PE liners, not only the material, but also the type of sterilization is of major importance for the mechanical properties and for the biological effects. Until the mid-1990s, the most common sterilization method for UHMWPE was gamma irradiation. Whilst this method increases cross-linking between PE molecules, generating a more wear-resistant material, when performed in presence of oxygen, it also produces free radicals. Free radical oxidation makes PE more brittle, with reduced resistance and increased wear. Several studies highlighted how the use of a different sterilization method improves PE wear resistance.21-23 Thermal sterilization with gas plasma has been shown to improve wear and oxidation resistance in vitro when compared with gamma irradiation in the presence of oxygen. On the other hand, sterilization with gamma irradiation in an air-free environment and oxygen-free packaging could theoretically reduce the risk of free radical oxidation, while maintaining the increased cross-linking between PE molecules. In a ten-year follow-up study by Engh et al,24 PE liners sterilized by oxygen-free gamma irradiation showed less head penetration and less osteolysis when compared with both gas plasma and gamma irradiation in air. Thus, when choosing or revising a PE liner, a knowledge of the sterilization method is necessary. Oxygen-free packaging in gamma-irradiated PE should be the preferred method, together with PE sterilized in ethylene oxide; currently these show good clinical long-term results and are preferred by many sterilization stakeholders.

MoXLPE is, of course, a valid alternative bearing option, since as yet there is no long-term evidence on the superiority of one bearing surface over the others among the three best performing PEs (MoXLPE, CoXLPE, CoC). We personally do not see any reason for using a metal head instead of a ceramic one other than cost.

A Falcon 9 first-stage booster is a reusable rocket booster used on the Falcon 9 and Falcon Heavy orbital launch vehicles manufactured by SpaceX. The manufacture of first-stage booster constitutes about 60% of the launch price of a single expended Falcon 9[1] (and three of them over 80% of the launch price of an expended Falcon Heavy), which led SpaceX to develop a program dedicated to recovery and reuse of these boosters. After multiple attempts, some as early as 2010, at controlling the re-entry of the first stage after its separation from the second stage, the first successful controlled landing of a first stage occurred on 22 December 2015, on the first flight of the Full Thrust version. Since then, Falcon 9 first-stage boosters have been landed and recovered 386 times out of 398 attempts, including synchronized recoveries of the side-boosters of most Falcon Heavy flights.

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Falcon 9 B1062 launched Inspiration4 in 2021, operated by SpaceX on behalf of Shift4 Payments CEO Jared Isaacman.[282] The mission launched the Crew Dragon Resilience on 16 September 2021 at 00:02:56 UTC[a] from the Florida Kennedy Space Center's Launch Complex 39A atop a Falcon 9 launch vehicle, placed the Dragon capsule into low Earth orbit,[259] and ended successfully on 18 September 2021 at 23:06:49 UTC,[283] when the Resilience splashed down in the Atlantic Ocean. B1062 held the record for the fastest booster turnaround time at 21 days and 4 hours between 8 April 2022 (Axiom-1) and 29 April 2022 (Starlink Group 4–16) beating the previous record of 27 days and 6 hours held by B1060. This was the first time a booster had flown twice in the same calendar month. According to the SpaceX webcast of the Starlink Group 4-16 mission, the booster spent just nine days in refurbishment. This record withstood until B1080 broke it by launching within 14 days between 11-24 November 2024. This booster was the first booster to achieve 20 launches and landings. This booster completed 22 successful launch and landings, before tipping over on its 23rd landing on the droneship A Shortfall of Gravitas during the Starlink 8-6 mission.[284]

Boosters B1023 and B1025 were originally Falcon 9 boosters which were converted to Falcon Heavy side boosters for the Falcon Heavy test flight.

As of 20 December 2024[update], SpaceX has put into service a total of 45 new B5 boosters, of which 27 have been destroyed (19 have been expended, six have been lost due to failed landings, and two have been lost during recovery).

No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.

weight and body mass index do not influence the choice of the bearing, whilst in cases with major anatomical deformities, pre-operative high range of movement and soft-tissue laxity, CoC is used carefully – even if the patient is young.

Surface degradation due to electrochemical interactions producing metallic ions and salts which applies only to metals. Different distinct forms of corrosion have been described (galvanic, fretting, crevice, stress, etc).20

In the last 15 years, conventional PE liners have been progressively abandoned in favour of XLPE liners. Currently, XLPE is used in the 98% of THAs in which a PE liner is selected.5 XLPE is defined as UHMWPE that has been irradiated with at least 50 kGy of gamma (or beta) or electron beam radiation. This treatment induces the cross-linking between PE molecules, with the rationale of increasing wear resistance. In the last few years the first long-term follow-up studies have been published, and reduced wear, together with a better survival of XLPE when compared with standard PE were found.25,26 The better long-term results with XLPE were confirmed by registry data in the 2017 Australian Registry report. The rate of revision at 16 years for XLPE was 6.2%, compared with 11.7% for non-XLPE.5 It is worth noting that a recent study found an increase in wear rate in XLPE compared with standard PE starting from the tenth year of follow-up, thus raising a first concern on the very long-term performance of XLPE.27

Grasshopper began flight testing in September 2012 with a brief, three-second hop, followed by a second hop in November 2012 with an 8-second flight that took the testbed approximately 5.4 m (18 ft) off the ground, and a third flight in December 2012 of 29 seconds duration, with extended hover under rocket engine power, in which it ascended to an altitude of 40 m (130 ft) before descending under rocket power to come to a successful vertical landing.[238] Grasshopper made its eighth, and final, test flight on 7 October 2013, flying to an altitude of 744 m (2,441 ft) before making its eighth successful vertical landing.[239] Grasshopper is retired.[11]

The booster expended after 1 use was B1054, (GPS III SV01 to MEO, Dec 2018). The three boosters destroyed on their first flight include two FH cores : B1055 (fell off ship, Apr 2019) and B1057 (ADS landing fail, June 2019).

Currently, several options are available to the surgeon when choosing the bearing surface in THA (Table 1). The most common material for acetabular liners is polyethylene (PE), either ultra-high molecular weight PE (UHMWPE) (the so-called ‘standard’ or ‘conventional’ PE) or cross-linked UHMWPE (XLPE), or ceramics or metal; the latter nowadays abandoned and withdrawn from the market for THA.13 Heads can be made of ceramics or metal alloys, usually CoCr (Cobalt-Chromium).14 Thus, there are several combinations of liners and heads that can be selected, each one with its own well-known advantages, but also disadvantages (Table 1).15 Wear and osteolysis are described as occurring mainly with conventional PE bearings associated with metal or ceramic heads (MoPE or CoPE). XLPE has been reported with less wear (MoXLPE or CoXLPE), but also with a decrease in mechanical proprieties; ceramic-on-ceramic (CoC) is related to much less wear and the highest bio-tolerability but carries the risk of breakage and noise from the implant following arthroplasty. Very few studies have directly compared the various combinations of bearings at long-term follow-up. Randomized controlled trials (RCTs) show similar short- to mid-term survivorship among CoC, CoXLPE and MoXLPE in patients younger than 65 years.16 Thus, clinical decisions on the choice of the bearing are still based on very limited evidence.17

Recently, XLPE liners with the addition of antioxidants such as Vitamin E were introduced into the market with the aim of reducing the oxidation in vivo. The Vitamin E can be mixed in PE powder or added through diffusion after machining. The rationale for Vitamin E addition is to act as an antioxidant reacting with the free radicals that remain instead of oxygen.33 In this way, re-melting is not necessary to avoid the oxidation, and mechanical properties are saved. As a consequence, the liner can also be thinner and larger heads can be used, with a possible improvement in joint stability. While the early clinical results are promising, with a low wear rate reported even with 36-mm diameter heads, the follow-up is still too short to evaluate potential clinical advantages over regular XLPE liners34-36 and registry data show no difference between XLPE and Vitamin E XLPE.5

When choosing the surface bearing, the surgeon must keep in mind that not all XLPEs are the same; the dimension changes with different acetabular components and head size but a minimum thickness must be preserved. Also, the ceramics are not always the same, and in the case of CoC the metal-back features (thickness, shape, surface finishing, press fit) and implantation tools can make a great difference. These features differ from one brand to another. Concerning hard bearings, clinical studies on large numbers and registry data are not yet able to evaluate whether wear performances are influenced by surgical technique, the handling and the position of the components, the acetabulum size, the hardness of the bone, the presence of osteophytes, the soft-tissue balancing or restoration of the anatomy. For these reasons, proper training for the surgeon who is willing to use hard bearings such as ceramics should be mandatory.75

Intra-operative measurement of acetabular components and liner of a total hip arthroplasty: a) the metal back has a minimum thickness that must be taken into account; b) a minimum polyethylene (PE) thickness must be preserved even when selecting large diameter femoral heads; c) ceramic liners can be thinner than PE liners.

Two potential limitations to the use of ceramic heads are worth discussing: the risk of fractures and the increased costs. While a detailed explanation of ceramic fracture mechanisms is given below, it must be noted that the risk of head fracture is lower than the risk of liner fracture and is reported as occasional and insignificant in combination with PE.50 A clean engagement of the head in the stem taper is required to reduce fracture risk. Concerning the costs, ceramic heads are more expensive than metal heads. However, in a model that accounted for the increased risk of trunnionosis with metal heads, the routine use of ceramic heads has showed comparable cost-effectiveness to metal heads.51 No population-based studies have estimated the real-life cost-effectiveness of routine ceramic head use. With the increasing use of ceramic heads, we can expect that the price will decrease and, at the same price as metal heads, there should be no objections to the claim that CoXLPE could be preferable to MoXLPE.2

This chart displays the turnaround time, in days, between two flights of each booster. As of 13 December 2024[update], the shortest turnaround time was 14 days, for the thirteenth flight of B1080. Boosters that are still likely to be re-used (active fleet) are highlighted in bold.

B1056 first launched on 4 May 2019, carrying a Cargo Dragon to the ISS. Because of the failure of the static test fire of Crew Dragon C204's Super-Draco abort engines on LZ-1, it landed on a drone ship instead.[272] It flew three more times. On 17 February 2020, B1056 was planned to perform the 50th orbital-class rocket landing, just 27 days after its previous launch.[273] The booster soft-landed in the Atlantic Ocean and was severely damaged after launching Starlink satellites into orbit, becoming the first flight-proven Block 5 booster to fail landing.[137]

SpaceX inventory

The Falcon 9 has evolved through several versions: v1.0 was launched five times from 2010 to 2013, v1.1 launched 15 times from 2013 to 2016, Full Thrust launched 36 times from 2015 to 2015. The most recent version, Block 5, was introduced in May 2018.[235] With each iteration, the Falcon 9 has become more powerful and capable of vertical landing. As vertical landings became more commonplace, SpaceX focused on streamlining the refurbishment process for boosters, making it faster and more cost-effective.[4]

Booster names are a B followed by a four-digit number. The first Falcon 9 version, v1.0, had boosters B0001 to B0007. All following boosters were numbered sequentially starting at B1001, the number 1 standing for first-stage booster.

Conventional and cross-linked polyethylene PE liners are the most common choice in THA. UHMWPE was introduced in the early 1960s by Charnley, and was widely used until the last decade, when it has been progressively replaced by XLPE.

over the age of 65 years: CoXLPE (28 mm, 32 mm or 36 mm depending on the acetabular component size and on the risk of dislocation of the patient. In high-risk patients, dual mobility acetabular components are used);

B1048 was the third Falcon 9 Block 5 to fly and the second Block 5 booster to re-fly, and the first booster ever to be launched four, then five times. During the last launch, an engine shut down seconds before the planned shutdown, becoming only the second time a Merlin engine failed since the failure during the SpaceX CRS-1 in October 2012. The primary mission was unaffected and the Starlink payload deployed successfully,[263] further confirming the reliability of the rocket due to redundancy of the engines. With reduced thrust, B1048 was unable to sufficiently slow down its descent, and thus was unable to land.[264]

In total 44 recovered boosters have been refurbished and subsequently flown at least a second time, with a record of 24 launches and landings carried out by a single booster. SpaceX intentionally limited Block 3 and Block 4 boosters to flying only two missions each,[2][3] but the company indicated in 2018 that they expected the Block 5 versions to achieve at least ten flights, with only minor refurbishment between missions. The ten flight milestone was first achieved by Booster B1051 on the Starlink 27 mission in 2021.[4]

B1050 launched for the first time on 5 December 2018.[267][268] A grid fin malfunction occurred shortly after the entry burn, resulting in the booster performing a controlled landing in the ocean instead of the planned ground pad landing.[269]

B1051 was the sixth Falcon 9 Block 5 booster built. On its maiden flight on 2 March 2019, it carried a Crew Dragon into orbit on the Demo-1 mission. It then flew its second mission out of Vandenberg AFB launching the Radarsat constellation. It then flew 4 Starlink missions and launched SXM-7, totaling 5 flights in 2020 alone, and becoming the first Falcon 9 to launch a commercial payload on its seventh flight. On 18 December 2021, it flew for a record 11th time.[271] It was the first booster to be used eight, nine, ten, eleven, and twelve times respectively. It flew for the final time on 12 November 2022 for the Intelsat G-31/G-32 mission, and was expended.

B1062

Two other main factors need to be considered when evaluating the long-term performance of a PE liner: the diameter and the material of the femoral head. Larger diameter heads are associated with increased wear and revision rate for osteolysis when coupled with standard PE.5,37 Interestingly, no increase in XLPE wear rate with the use of larger diameter heads (> 32 mm) was reported.38 Moreover, good results with XLPE at a medium-term follow-up were reported even with the use of large diameter ceramic heads.39 These observations were recently confirmed by registry data that reported a ten-year survival of 95.3% of THA with XLPE and a femoral head > 32 mm.5 These data could allow surgeons to use larger femoral heads even when selecting a XLPE liner, but in standard routine cases no more than 36 mm is suggested according to the acetabular component size for safety reasons, as there is a lack of information for head sizes larger than 36 mm. The thickness of XLPE should provide enough fatigue resistance to the components. For this purpose, the design must also be considered. In our experience, we use larger femoral heads when we can select a XLPE liner with a minimum thickness of 6 mm, that means in acetabular components with a minimum size of 56 mm40 (Fig. 1).

This chart shows how many boosters have had N flights, and their status: whether they are still active, expended (i.e. no attempt was made to recover) or destroyed (i.e. recovery of the booster failed).

Notes: XLPE, highly cross-linked polyethylene; ARMD, adverse reaction to metal debris; ALVAL, aseptic lymphocyte-dominant, vasculitis-associated lesion

Metal on metal THA has a long history which began in the 1950s and 1960s in the United Kingdom with McKee-Farrar. In the 1980s, small MoM heads (28 mm and 32 mm) by Weber and Semlitsh became quite popular, even if they never gained a major role in the market. Acceptable results are reported with small MoM heads both by registries3 and clinical studies at medium- to long-term follow-up.71-74 Unfortunately, due to the high rate of failure and of adverse reactions to metal debris following the MoM big heads introduced in the middle of the 2000s and despite the early favourable outcome of hip resurfacing, MoM THA is nowadays almost entirely abandoned by surgeons and completely withdrawn from the market by manufacturers, including small heads. This bearing surface is no longer an option and the issue nowadays is how to follow-up patients implanted with MoM in the past.13

B1023 and B1025 were assigned the role of side boosters for the Falcon Heavy test flight in 2017, after which they underwent separate static fire tests. The boosters were mated to a newly built Falcon Heavy core, B1033, for the flight.[257] The maiden flight of Falcon Heavy on 6 February 2018 launched SpaceX CEO Elon Musk's Tesla Roadster and a dummy astronaut into a Mars-crossing heliocentric orbit. The boosters successfully separated from the core and performed synchronized landings on LZ-1 and LZ-2.[258]

There are three booster types: Falcon 9 (F9), Falcon Heavy core (FH core) boosters, and Falcon Heavy side (FH side) boosters. Falcon 9 and Falcon Heavy side boosters are reconfigurable to each other. A Falcon Heavy core booster is manufactured with structural supports for the side boosters and cannot be converted to a Falcon 9 booster or Falcon Heavy side booster.[citation needed] The interstage mounting hardware was changed after B1056. The newer interstage design features fewer pins holding the interstage on, reducing the amount of work needed to convert a Falcon 9 booster to a Falcon Heavy side booster.[82]

Rockets from the Falcon 9 family have been launched 425 times over 15 years, resulting in 422 full successes (99.29%), two in-flight failures (SpaceX CRS-7 and Starlink Group 9–3), and one partial success (SpaceX CRS-1, which delivered its cargo to the International Space Station (ISS), but a secondary payload was stranded in a lower-than-planned orbit). Additionally, one rocket and its payload (AMOS-6) were destroyed before launch in preparation for an on-pad static fire test. The active version of the rocket, the Falcon 9 Block 5, has flown 357 times successfully and failed once, resulting in the 99.72% success rate.

Correct positioning and handling of the components is very sensitive in the case of CoC, which has a very low wear bearing surface, but is less forgiving. Also, metal back deformation60 during the insertion is critical as titanium shell can deform during impaction, consequently generating a two-point support of the liner to which ceramics are vulnerable.61 Thus, careful preparation of the acetabulum and assessment with a trial insert is required when using a ceramic liner. Not all the metal backs are the same in terms of thickness, stiffness and tools for implantation. A small change can cause a big difference during engagement of the taper of the ceramic liner in the shell. This could be due to a flawed design of the components or to a surgical fault. Again, intra-operatively each implant must be checked for correct engagement of the liner in the metal back prior to the definitive reduction of the prosthesis.

CoC bearings have some drawbacks that limit their widespread use. The first limitation of ceramics is the brittleness of the material that increases the risk of fracture. Ceramic fracture is indeed a catastrophic complication that can occur with the use of such material. With modern ceramics, studies report only occasional occurrence of fracture of the head, with higher risk of occurrence in the short neck 28-mm head.56 Liner fracture has been reported with a higher frequency, with percentages between 0.13% to 1.1%, with differences among metal-backed brands.57,58 Liner fractures are almost never related to direct trauma, but rather depend on three main mechanisms: misalignment during insertion of the liner, metal back damage or acetabular component malposition that leads to impingement and edge-loading. Excessive anteversion (> 25°) has been demonstrated as the main clinical risk factor for liner fracture due to impingement.59

In this paper, a brief review of the main advantages and drawbacks of various types of tribology in THA will be discussed, while providing practical suggestions for the surgeon on the most acceptable bearing surface option for each patient, based also on the extensive personal experience of the authors.

The cross-linking process, while increasing the wear properties of PE decreases the mechanical ones, making the liners more at risk of fatigue fracture. The irradiation of PE generates free radicals that can react with oxygen and could compromise the mechanical properties over time.29 As a matter of fact, breakage of XLPE liners has been widely described in particular when old types of locking mechanism and designs were used.30,31 Moreover, steep positioning of the acetabular component which leads to stresses concentration or impingement is considered a risk factor.32

Currently, several options are available to the surgeon when choosing the bearing surface in THA (ceramic-on-ceramic (CoC), ceramic-on-polyethylene (CoPE), metal-on-polyethylene (MoPE)), each with advantages and drawbacks.

Falcon 9 first-stage boosters landed successfully in 386 of 398 attempts (97%), with 361 out of 366 (98.6%) for the Falcon 9 Block 5 version. A total of 360 re-flights of first stage boosters have all successfully launched their second stages and, all but one, their payloads.

B1023 became the third orbital-class rocket to land on a droneship after launching Thaicom 8 into a geostationary transfer orbit on 27 May 2016. It was an unusually hard landing that crushed the energy absorbers on at least one of the landing legs, causing the booster to "walk" across the droneship and lean over,[251][252] but the rocket arrived safely at Port Canaveral.[253] B1025[254] successfully launched the CRS-9 resupply mission on its maiden flight on 18 July 2016 and landed on LZ-1, being the first after B1019 to do so.[255] The mission carried a new docking adapter specifically designed for autonomous spacecraft to the ISS in preparation for Dragon 2 resupply and Commercial Crew missions.[256]