11
$\begingroup$

The Dragon capsule landed yesterday, and I saw this picture of it:

enter image description here

Historically, capsules had a rather large uncertainty when landing, especially with parachutes. This picture was obviously taken while the capsule was still in the air, but close to ground, from the air, and must have been relatively close. How does the uncertainty of Dragon compare to Soyuz in terms of it's landing accuracy?

$\endgroup$
  • $\begingroup$ Don't underestimate the power of a long lens. You can also track the Dragon from high altitude and start flying towards it, so this picture alone doesn't indicate much. $\endgroup$ – Hobbes May 12 '16 at 17:35
  • $\begingroup$ @Hobbes Fair enough, but I imagine that you couldn't do this with a miss distance of, say 100 miles. $\endgroup$ – PearsonArtPhoto May 12 '16 at 17:40
  • $\begingroup$ @PearsonArtPhoto: Soyuz maneuvers in a controlled glide on its heatshield during the descent before opening the parachutes, so it can quite fine-tune its ballistic trajectory and apply last-minute corrections for wind predicting the drift on parachutes. It's only wind variability during the parachute descent that is the source of error. I don't know about Dragon, but with it being a newer design I'd be surprised if it couldn't do that. $\endgroup$ – SF. May 12 '16 at 21:42
  • $\begingroup$ Suggested an edit to clarify this is for the Dragon under parachutes; Dragon 2's propulsive landing will be a different story. $\endgroup$ – DylanSp Mar 20 '17 at 15:02
7
$\begingroup$

No values for Soyuz or Dragon on wiki splashdown page, but the lake listed for the one Soyuz water landing seems to be like 20x40km. NASA shows the Soyuz landing zone as 25km wide.

There is a thread on NSF where the users posted some graphs of landing accuracy, one of them showing the SpaceX COTS-1 and claiming the precision (0.8km) was much better than average Soyuz and even better than the best of Soyuz TMA-04M (2.2km):

Soyuz landing accuracy

user Comga, forum.nasaspaceflight.com

For Dragon landings there is a map posted by reddit user Raul74Cz but no hard numbers in there, only estimates based on reentry areas (which - being the expected worst case - are quite big). I was not yet able to find some exact values for other Dragon landings, articles only mentioning the landings being "precise" with the recovery vessels being "near" the spot and quick to get to the capsule.

2017-03-19 this image was tweeted by SpaceX Dragon CRS-10 descending on her chutes

It shows the CRS-10 Dragon capsule still in the air being photographed by the recovery crew. I found no data about the focal lenght or similar which would allow to estimate the actual distance but it is visible and does not look too far. Taking into account that the recovery vessels probably stay out of the designated zone, it may be just a lucky coincidence but it being not a first such photo suggests it is not just random chance.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.