from Hacker News

X-37B plane can stay in space for years, power source?

by MysticFear on 10/12/14, 4:05 PM with 19 comments

• by gvb on 10/12/14, 4:56 PM

  It is extremely likely it is the hypergolic fuel used for the on-orbit manoeuvring rockets. Hypergolic fuel is really nasty stuff.

  It is likely the same rocket fuel (maybe the same rockets) as used by the space shuttle (OMS).

  http://en.wikipedia.org/wiki/Space_Shuttle_Orbital_Maneuveri...

  See also:

  * http://en.wikipedia.org/wiki/Space_Shuttle_Discovery#Decommi...

  * http://en.wikipedia.org/wiki/Hypergolic_propellant#Disadvant...

• by dalke on 10/12/14, 5:09 PM

  That's chemical protective gear designed to protect the ground crew against hydrazine or similarly hazardous vapors .

  They were first developed in the 1960s for the Titan missiles, which use the chemically nasty (but room temperature) nitrogen tetroxide and Aerozine 50. See http://books.google.com/books?id=MdTZFu1fZ4AC&pg=PA186&lpg=P... for some of the history.

  Here you can see the suits in use at the end of the Space Shuttle STS-1 mission: http://www.youtube.com/watch?feature=player_detailpage&v=gYc... along with explanation by both the news and NASA commentators.

  http://www.xcor.com/blog/category/thrusters/ and http://www.esa.int/Our_Activities/Space_Engineering/Clean_Sp... are pictures of people in similar suits, in order to fuel spacecraft. I picked those to give commentary about how hazardous hydrazine is, and that there's a push to use alternative fuels.

• by Hoff on 10/12/14, 5:26 PM

  Months are not a particularly long duration for spacecraft, and solar arrays are not at all unusual as power sources for spacecraft in the inner solar system.

  Some data on satellite lifetimes:

  * http://www.ospo.noaa.gov/Operations/GOES/status.html

  * http://noaasis.noaa.gov/NOAASIS/ml/life_expectancy.html

  * http://noaasis.noaa.gov/NOAASIS/pubs/life%20expectancy.pdf (2009)

  As for the protective equipment being used in that Yahoo photo, that's probably due to the use of hypergolic fuel:

  * http://en.wikipedia.org/wiki/Hypergolic_propellant

  Notice nearly-identical protective equipment being used in the Wikipedia entry.

  As for protective equipment for radioisotope thermoelectric generators, here's an example from Cassini:

  * http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_gen...

  This being the Internet, there's far more information on related topics available:

  * http://en.wikipedia.org/wiki/Corona_(satellite)

  * http://en.wikipedia.org/wiki/File:U.S._RecSat_Big_Picture.jp...

  Hmmm. Wonder what other and far more familiar satellite that KH-11 Kennan looks like.

  * http://en.wikipedia.org/wiki/File:HST-SM4.jpeg

• by jeroen on 10/12/14, 4:52 PM

  Clickable url

  http://news.yahoo.com/secretive-x-37b-military-space-plane-c...

• by JabavuAdams on 10/12/14, 4:55 PM

  The protective equipment is probably for fuel or oxidizer leaks.

  This page: http://www.airforce-technology.com/projects/boeing-x37/

  says that the vehicle uses either hydrazine or nitrogen tetroxide.

  Aside from the main engine, reaction thrusters could foul the surrounding fuselage with nasty chemicals.

• by stevengg on 10/12/14, 5:07 PM

  the guy who took this picture gave a talk 30c3 he takes pictures of military instantiations Seeing The Secret State: Six Landscapes

  http://media.ccc.de/browse/congress/2013/30C3_-_5604_-_en_-_...

• by qwerta on 10/12/14, 4:55 PM

  I guess the fuel could be poisoning (that was case for some soviet military rockets). Other option is just caution not to introduce dust particles etc...

• by exabrial on 10/12/14, 7:23 PM

  Exact same suits being worn here...

  http://en.wikipedia.org/wiki/Hydrazine#mediaviewer/File:Hype...

• by anovikov on 10/12/14, 5:10 PM

  It is simply an MMH or UDMH propellant onboard, which is carcinogenic.

• by benologist on 10/12/14, 4:39 PM

  Apparently this thing can fly 500 miles high which is space, maybe it's related to that?

  http://www.space.com/25275-x37b-space-plane.html

  http://en.wikipedia.org/wiki/Outer_space#Boundary