Quote from: sdsds on 12/23/2023 06:08 pmSadly, Celestrak data (https://celestrak.org/NORAD/elements/table.php?INTDES=2023-202) seem to indicate that atmospheric drag is winning.The Celestrak data looks to me like there is ONLY a slow orbital decay happening.I don't see evidence for any significant spacecraft thrusting taking place- or if any is, as you note drag is winning.
Sadly, Celestrak data (https://celestrak.org/NORAD/elements/table.php?INTDES=2023-202) seem to indicate that atmospheric drag is winning.
Something to remember with orbit decay is that the rate of decay speeds up exponentially as altitude decreases.
Can anyone explain what’s going on here? Is this change of slope of SMA due to a real ongoing transfer of orbital energy from B to A?Or is it an artifact of how Celestrak plots SMA (as altitude rather than apogee and perigee separately)?Anyway, the plot seems to suggest that A (presumably the Lockheed ESA payload) will last a tad longer than previously expected.
Quote from: VLN on 12/29/2023 02:31 amCan anyone explain what’s going on here? Is this change of slope of SMA due to a real ongoing transfer of orbital energy from B to A?Or is it an artifact of how Celestrak plots SMA (as altitude rather than apogee and perigee separately)?Anyway, the plot seems to suggest that A (presumably the Lockheed ESA payload) will last a tad longer than previously expected.My guess is nothing physically happened but the software that decides which radar returns belong to which object had a bad day and swapped the two objects for the last point in time. If you plot object B's last SMA and eccentricity on object A's plot and vice versa the last point in time continues the trend lines.
58616 TYVAK-1015 (TANTRUM) 2023-202A 140.01 501 21458617 FIREFLY ALPHA R/B 2023-202B 140.02 487 210
ORLANDO, Fla. — A Lockheed Martin satellite that was placed in the wrong orbit Dec. 22 is expected to de-orbit in February. Despite a much shortened mission, the company said it successfully accomplished many of the objectives of the technology demonstration....Bob Behnken, director of technology acceleration at Lockheed Martin Space, told SpaceNews in a statement that the company’s antenna technology demonstration payload “exceeded our expectations and successfully completed all primary mission objectives. This feat is even more impressive in light of the spacecraft being placed in an unplanned, lower orbit, which resulted in a dramatically compressed mission timeline.”...From the lower orbit location, he said, “we’ve completed more than 100 payload testing events to date, and continue to achieve more each day.”
January 31, 2024“As Firefly communicated in the immediate hours following Alpha FLTA004, we experienced a mishap when the second stage failed to achieve the planned target orbit for payload deployment. The subsequent investigation is progressing very well, and we will have more information to share in the weeks ahead as we wrap up our review and take corrective action. As part of that process, we invited our mission partner and future customers to serve as external oversight of the investigation for full transparency, and that exchange has been extremely valuable for the entire community.Despite these challenges, the Firefly team placed our mission partner in an orbit where they successfully completed their primary mission objectives, including rapid commissioning of the satellite following insertion. Before communicating any further mission-related status on our partner’s payload, we waited until their confirmation of performance and success, which they released in a recent statement.Ultimately, the important long-term outcome is the rapid, thorough maturation of Alpha as the dependable one metric ton class rocket the market is demanding, which Firefly is dedicated to and is delivering. In the near term, it is a testament to the hard work and commitment of Firefly as a company that we were able to work alongside our partner to achieve this positive outcome.” – Bill Weber, CEO of Firefly Aerospace
[...] So Feb 14, 2024 looks like the No Later Than date for re-entry.
Tantrum reported to have reentered sometime between 1426 and 1518 UTC Feb 10. That almost 1 hr uncertainty corresponds to a track from Brazil to S Africa to NW Australia to Papua to Wake Island.
https://spacenews.com/lockheed-martins-misplaced-satellite-to-fall-back-to-earth-next-month/QuoteORLANDO, Fla. — A Lockheed Martin satellite that was placed in the wrong orbit Dec. 22 is expected to de-orbit in February. Despite a much shortened mission, the company said it successfully accomplished many of the objectives of the technology demonstration....Bob Behnken, director of technology acceleration at Lockheed Martin Space, told SpaceNews in a statement that the company’s antenna technology demonstration payload “exceeded our expectations and successfully completed all primary mission objectives. This feat is even more impressive in light of the spacecraft being placed in an unplanned, lower orbit, which resulted in a dramatically compressed mission timeline.”...From the lower orbit location, he said, “we’ve completed more than 100 payload testing events to date, and continue to achieve more each day.”edit/gongora: trimmed, do not post copyrighted articles in their entirety
The payload maker & operator claims 100% success for their mission, despite the failure to reach the intended orbit. It seems to me that makes the Firefly Alpha FLTA004 mission success close to 100% also, because of the fortuitously relaxed needs of the customer.
The payload maker & operator claims 100% success for their mission, despite the failure to reach the intended orbit. It seems to me that makes the Firefly Alpha FLTA004 mission success close to 100% also, because of the fortuitously relaxed needs of the customer.Of course, we also hope Firefly will be able sort out the second stage problem so that a normal customer mission can be fully satisfied.
Our dedicated team has completed the flight data review for Alpha FLTA004 and determined root cause after Alpha’s second stage did not achieve the target orbit for payload deployment. With corrective actions underway, Alpha will be ready to fly again in the coming months. Learn more here: https://fireflyspace.com/missions/fly-the-lightning/
…The investigation determined the mishap was due to an error in the Guidance, Navigation, and Control (GNC) software algorithm that prevented the system from sending the necessary pulse commands to the Reaction Control System (RCS) thrusters ahead of the stage two engine relight.…… Firefly is now implementing corrections actions to ensure the GNC software issue is resolved, including process changes to detect and prevent similar issues in the future. Alpha will be ready to fly again in the coming months.
Software again - writing reliable code is hard.So my question is, were the RCS commands supposed to perform propellant settling, and the engine didn’t fire, or was it supposed to set/stabilize attitude, meaning engine fire was in the wrong direction?
just adding a comment to the above posthttps://twitter.com/DJSnM/status/1759954805584203955QuoteSoftware again - writing reliable code is hard.So my question is, were the RCS commands supposed to perform propellant settling, and the engine didn’t fire, or was it supposed to set/stabilize attitude, meaning engine fire was in the wrong direction?
