Meta & Fysikken: Afsnit 61: Diverse nyt fra jord & rum
I dette afsnit samler vi op på en række forskellige områder. Og vi kommer lidt ind på krig her på jorden, og hvordan det måske/måske ikke får indflydelse på hvad der foregår i de internationale forskningsmiljøer.
Her er lidt noter til dagens afsnit:
1. Ikke Falcon 9 upper stage der rammer Månen men CZ-3C Y12 third stage from China's Chang'e-5T1 lunar test mission fra 2014.
Fra Jonathan McDowell. Det er ham man skal følge hvis man gerne vil vide hvad der rør sig.
https://planet4589.org/space/jsr/jsr.html
Further analysis by Bill Gray shows that an upper stage, abandoned
since 2014, will actually impact the lunar farside at around 1222 UTC
Mar 4. Originally thought to be a Falcon 9 upper stage from the 2015
DSCOVR launch, further backtracking of the orbit data now shows that it
is actually the CZ-3C Y12 third stage from China's Chang'e-5T1 lunar
test mission, launched in Oct 2014. (China issued a confusing statement
saying it wasn't the booster from Chang'e-5 - the 2020 followon mission -
which no-one was claiming it was anyway).
Following a flyby of the Moon soon after launch, the stage remained
in a 350000 x 565000 km x 57.4 deg deep Earth orbit in
the outer part of the Earth-Moon system. The perigee was close to lunar
distance, making eventual further lunar encounters inevitable. Orbits
like this are somewhat chaotic, their orbital parameters strongly
affected over time by lunar and solar gravity as well as the Earth.
Further lunar flybys occurred: 23573 km on 2016 Jan 17, and 9312 km on
2022 Jan 5. This last flyby sent the stage on an elliptical
orbit that came as low as 25000 km from the Earth, on Jan 21, then out
again to lunar distance. It will come back in to 45000 km perigee on
Feb 9 on a path for a fatal last apogee at 688000 km on Feb 23 from
which it will fall back in to hit the Moon on Mar 4.
The stage is about 4 tonnes (4000 kg) and it will hit the Moon at 2.5 km/s. (9000 km/h)
We know lots of junk from lunar missions has ended up hitting the Moon,
for example upper stages from lunar missions and junk left in lunar
orbit. The LCROSS mission deliberately smashed a Centaur stage (similar size)
into the Moon on 2009 Oct 9, with a special spacecraft following behind
it to study the impact.
This is the first time that something not explicitly targeted at
the Moon has been noticed to accidentally hit it, but that's mainly
because we weren't paying attention until recently. Thanks to Bill Gray
and a few other people who have spent their own time keeping track of
the space junk that's too far out for SpaceForce to care about, we can
now spot events like this. Amazingly it is no one's paid job to do -
the fact that the stage was initially misidentified adds emphasis to
our lack of knowledge of the artificial objects abandoned in cislunar space.
There are about 30 to 50 lost deep space objects like this that have
been missing for years - 50 years in some cases - that haven't been
picked up by asteroid searches, and probably some of them hit the moon
without us noticing. This is not 'the launch agency did something bad' - it's
perfectly standard practice to abandon stuff in deep orbit - this is
'none of the space agencies care about leaving stuff out beyond the
Moon'.
Traffic in deep space is increasing. And it's not like the old days with
just the USA and the USSR sending stuff to deep space, it's many countries and even
commercial companies like SpaceX. So I think it's time for the world to
get more serious about regulating and cataloging deep space activity.
Thanks to Bill Gray and Dan Adamo for sterling astrodynamics work
sorting this out.
Oh, and where is the DSCOVR booster? Based on extrapolation of
a dataset provided by SpaceX, Dan Adamo derives a prediction which
implies it left the Earth-Moon system in March 2015 and is now
in a 0.95 x 0.99 AU x 0.1 deg heliocentric orbit.https://www.sciencealert.com/it-might-not-be-a-spacex-rocket-that-s-about-to-hit-the-moon
2) ESA har en Near Earth Orbit Risk list:
Man kan klikke sig ind og sortere efter str. eller risiko.
Størst risiko er en 8 m stor asteroide, der har 7% risiko for at ramme
https://neo.ssa.esa.int/risk-list
De har også en prioritets liste med positioner af NEO, hvilke vi helst vil have observationer (check af pos.) på.
July 2023, asteroid 2022 AE1 will fly by Earth at a distance of about ten million kilometres (+/- one million km) – more than 20 times the distance of the Moon.
3) Kinas Lunar-Rover Yuto-2 har lige fundet en lille glaskugle.
https://en.wikipedia.org/wiki/Yutu-2
https://www.sciencealert.com/the-moon-has-glass-balls
På månen siden Jan 2019. Har kørt 1 km, 140 kg
Glas kugler er helt almindeligt. Varme og Silicate. Lyn i ørkenen laver også sjove glas træer.
4) Solen er meget aktiv for tiden
Direkte konsekvens for Starlink (4.2.2022)
Det gør at atmosfæren har suget lidt mere energi til sig og dermed er blevet lidt mere tæt (tætheden er blevet større). Der var ekstra modstand (drag) fra atmosfæren så de blev nød til at putte satelitterne i 'safe-mode'. Omkring 40 af dem har ikke formået at gå ud af safemode og dermed evner de heller ikke at øge deres højde.
Det har betydet at 40 af det sidste kuld af star link satelitter på 49 stk ikke klarede det og de vil falde ned igen inden for et par dage.
Når nu vi snakker om Starlink. Astronomer er gået sammen og har kontaktet COPUOS (UN / FN Committee on the Peaceful Uses of Outer Space ) om at finde en bedre beskyttelse af Jordens mørke og stille himmel.