Today for my last day of tweeting, I want to talk about highlights from #MarsExpress & later from @esamarswebcam! This thread will be some highlights from the mission as a whole . This fantastic image is from HRSC https://www.dlr.de/content/en/articles/news/2019/03/20190919_mars-marvellous-from-north-pole-to-southern-highlands.html (: ESA/DLR/FU Berlin)

(I talked about the background of the #MarsExpress mission in this thread a few days ago). Now, onto some science/mission/fun highlights! https://twitter.com/People_Of_Space/status/1262093239429013508?s=20

First, a fun one! (sorry for *spoilers*!! ) Following on from me declaring my love for 'The Martian' yesterday, HRSC on #MarsExpress mapped out the route Mark Watney takes, and also reconstructed that journey in 3D! (: ESA/DLR/FU Berlin)

What about water on Mars? In 2018 the radar instrument MARSIS on #MarsExpress detected evidence of a subglacial lake the south polar cap! The bright radar echo is interpreted as the interface between ice & a stable body of liquid (salty ) water! https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Mars_Express_detects_liquid_water_hidden_under_planet_s_south_pole

Elsewhere, the #MarsExpress mission has also contributed significantly to the (controversial!) story of methane on Mars . Methane was tentatively detected early in the MEX mission but remained controversial within the scientific community: https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Mars_methane_and_mysteries

Last year, the PFS instrument on #MarsExpress published an independent confirmation of a methane spike on Mars seen by @MarsCuriosity, and suggested a source region east of Gale Crater . Methane is interesting because it *could* be related to life https://twitter.com/esascience/status/1112744858576474114?s=20

I particularly liked this piece by @kchangnyt in the New York Times which discusses a new spike found by @MarsCuriosity in June 2019, but also details the methane story which includes the measurements from #MarsExpress https://www.nytimes.com/2019/06/22/science/nasa-mars-rover-life.html

Another #MarsExpress highlight is the estimation of the current rate of atmospheric escape using data from the ASPERA instrument! https://sci.esa.int/web/mars-express/-/51826-6-estimation-of-the-current-rate-of-atmospheric-escape (Unfortunately Twitter botches the quality of videos, see it in better quality here: https://sci.esa.int/web/mars-express/-/44275-solar-wind-and-mars-atmosphere) (: ESA)

Investigations into atmospheric loss are important for determing how Mars lost its early atmosphere . A 'warm & wet' early Mars is evidenced by features we see today such as those present in this HRSC image of Arda Valles ( http://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Footprints_of_a_martian_flood) (: ESA/DLR/FU Berlin)

On the mission operations side of things, if you want to know more about how engineers like @marwood82 have kept #MarsExpress going for 16+ years () this is a great article by @richard_speed detailing that, including the switch to 'gyro-less' mode! https://www.theregister.co.uk/2020/03/31/mars_express/

I'll end with some of my favourite photos from HRSC, bc everyone loves pictures of Mars right? From upper left to bottom right: Perspective view of North Polar ice cap ; area near north pole; Olympus Mons Caldera ; Dark dunes of Moreux crater (all : ESA/DLR/FU Berlin)

More HRSC #MarsExpress photo highlights! From upper left to bottom right: Perspective view of Korolev crater; view of Deuteronilus Mensae showing evidence for glacial activity ; Perspective view in Noctis Labyrinthus; Phobos (one of the Martian moons) (: ESA/DLR/FU Berlin)

So, tldr; #MarsExpress mission highlights include the detection of a subglacial lake; detection of a methane spike; investigations into atmospheric escape on Mars; moving to a new 'gyroless' mode to extend the mission; and awesome pictures of Mars!! https://www.esa.int/Science_Exploration/Space_Science/Mars_Express