# How long do the ascent and the descent of Virgin Galactic's spacecraft take?

The VMS Eve mothership releases the VSS Unity spacecraft after ca. 48 minutes. The total duration is approximately 2 hours. As a result, the ascent time + the descent time that the Virgin Galactic's spacecraft takes is about 72 minutes, but I wonder what the breakdown between the ascent time and the descent time is.

## 1 Answer

This paper Biomedical monitoring of spaceflight participants during suborbital flights via agile architecture gives the following figure, showing four minutes of free fall.

The paper states that the powered flight portion lasts 70 seconds.

The paper goes on to say

the glide phase will begin with a return to an unpowered horizontal runway landing that will occur after a glide of 25 min. Total flight duration will be 150 min.

Perhaps they stretch out the flight to the drop altitude to last longer than an hour? Otherwise these numbers don't seem to add up.

• Thanks, perhaps gliding back to the spaceport takes a while? Commented Dec 26, 2020 at 22:02
• @FranckDernoncourt It must! At least for SS1, climbing to the drop altitude took about an hour (as you say) but SS1 ignition -> landing was only about 20 minutes which agrees with the info from this paper. en.wikipedia.org/wiki/SpaceShipOne_flight_17P Commented Dec 26, 2020 at 22:06
• I found some more info in the paper, will edit it in. Commented Dec 26, 2020 at 22:09
• "Perhaps they stretch out the flight to the drop altitude to last longer than an hour?" – I believe Eve is operating near her operating limits for those flights, which might partially explain why it takes her so long to climb. Additionally, they need to get enough separation from the airport, and turn back around such that in case Unity's rocket motor doesn't fire after release (as happened two weeks ago, for example), she can glide more or less straight down to the runway without having to circle back around or align with the runway. Commented Dec 27, 2020 at 12:44