Linked Questions

18 votes
2 answers
5k views

James Webb telescope; limits to propellant lifetime?

There is a comprehensive article on Wikipedia on the James Webb telescope. It includes a statement regarding the operational lifetime being nominally five years and optimistically ten years. However ...
Roger Wood's user avatar
  • 3,894
17 votes
2 answers
2k views

Why would a Deep Space Network antenna send up a carrier signal without any data?

Why would a Deep Space Network antenna send up a carrier signal to SOHO without any data? Source: https://eyes.nasa.gov/dsn/dsn.html . Is that some calibration process?
Some Student's user avatar
11 votes
4 answers
2k views

Are large halo orbits around L₁'s and L₂'s preferred over small orbits for reasons other than geometry?

There have been many examples of the placement of satellites in orbits around Lagrange points, most have been sun-earth and earth-moon $L_1$ and $L_2$ due to their proximity to earth. In each case ...
uhoh's user avatar
  • 148k
18 votes
2 answers
2k views

Is this what station keeping maneuvers look like, or just glitches in data? (SOHO via Horizons)

I've been enjoying the JPL Horizons web interface and after I discovered the incredibly extensive database associated with SOHO (Solar and Heliospheric Observatory, also see sohowww.nascom.nasa.gov) ...
uhoh's user avatar
  • 148k
18 votes
1 answer
7k views

What happens to JWST after it runs out of propellant?

JWST will be orbiting L2 which is unstable equilibrium thus will require propellant for station keeping. JWST will carry propellant for 5-10 years. What will happen once it runs out of propellant? ...
daniel.sedlacek's user avatar
5 votes
3 answers
2k views

How do spacecraft reach Lagrange points?

As I understand, to reach a Lagrange point the spacecraft would need to slow down. Also, can spacecraft passing nearby Lagrange points get captured within the point?
Bruce Vici's user avatar
5 votes
1 answer
391 views

Will WFIRST and JWST be able to resolve each other?

The James Webb Space Telescope is scheduled to launch in 2021 and be put in a halo orbit around Sun-Earth L2 soon after. The plan for the Wide Field Infrared Survey Telescope is a launch perhaps ...
uhoh's user avatar
  • 148k
6 votes
1 answer
482 views

Why put DSCOVR in a Lissajous orbit? Wouldn't a halo orbit completely avoid the Sun exclusion zone?

Halo orbits are a sub-class of Lissajous orbits. See this answer for (much) more on that. DSCOVR's orbit will put it in it's Sun Exclusion Zone in about 2020 where the communications line of sight ...
uhoh's user avatar
  • 148k
5 votes
1 answer
334 views

Where did the Herschel Space Telescope go in 2013?

The Herschel space telescope wins as largest optical telescope mirror in space when "optical" includes far infrared (~55 µm). The Wikipedia article Herschel Space Observatory lists the orbit ...
uhoh's user avatar
  • 148k
3 votes
1 answer
721 views

Rendezvouses in halo or lissajous orbits

If a spacecraft was in an EM-L2 halo/lissajous orbit, and another craft would was going to approach EM-L2 a few days later, could they rendezvous immediately or is there a limitation when the second ...
Bob516's user avatar
  • 6,999
4 votes
1 answer
393 views

Station-keeping delta-v per year for an Earth-Moon vanilla halo orbit?

This answer reminds us that an Earth-Moon L1 or L2 vanilla1 halo orbit remaining always visible to some patch on the Moon's surface requires station-keeping. Queqiao uses such an orbit having ...
uhoh's user avatar
  • 148k