They're working off the same license they used for test 5, so they basically have to exactly the same thing they did for test 5. They did manage to add this:
"An additional objective for this flight will be attempting an in-space burn using a single Raptor engine, further demonstrating the capabilities required to conduct a ship deorbit burn prior to orbital missions."
I think that's the last thing they need to do before they can actually launch satellites. I'm surprised there was no attempt on the last launch. Glad to see it this time. The improved Starlink constellation that Starship will enable is going to be awesome.
I think they will want to deal with heatshield first. As of now, it hasn't survived deorbiting.
SpaceX can launch satellites using Falcon9 and do it routinely. Starship needs to be developed and reach milestones, so they can get paid by NASA. Having a payload is a complication (unless it's a fun payload, remember the roadster car :D)
I think they can probably do both at once - heatshield testing and pez dispenser testing shouldn't interfere with each other, so might as well use whatever spare upmass you have!
Yeah you might lose the payload, but SpaceX has the cheapest satellites in the business from what I understand.
The next block of starship has an altered geometry/location of the flaps for that reason; it's more or less a solved problem, but not worth scrapping the older ones they've already built. Iirc, the launch after this one will be SN7, which is block 2 with the new geometry.
It's not a solved problem. Surviving the re-entry in a condition that makes reuse economical was always the biggest challenge for the Starship. It's far from certain that they can achieve it without a fundamental change in the concept.
The feasibility of building big rockets was already demonstrated a long time ago. Given the reliability of the Falcon 9, it looked plausible that a big rocket could work with many engines. And SpaceX had already shown that they can reuse boosters economically. But reusing orbital spacecraft – the entire upper stage with engines, fuel tanks, and whatever – without expensive and time-consuming refits is something nobody has done before.
If that part burning off is a solve problem then returning the orbital ship to the launchpad is too given that they are able to gently put it down on the sea, and that they are able to gently catch the booster. This part is basically the only problem left that is ship-specific. However for reuse (or rapid reuse) they might need to rethink heat shielding to reduce refurbishment time and cost.
That's cool PR move. If they managed to light one then it's great success. If they don't people will think they just got unlucky. But if they tried to light all and only one would work or none, or one would work but some other blew up whole rocket it would look terrible. That last eventuality is something they want to prevent by trying to light just one.
And they need to demo that the flaps hold up through re-entry with nominal, minimal damage, otherwise a permit for a plan involving re-entry over land (which is needed to catch the ship) would obviously not issue.
It's not groundbreaking but it's important. They are demonstrating in orbit relight capability of the raptor engines. This is an absolute requirement before they can put it fully into orbit because losing control of a Starship in low earth orbit would be catastrophic.
Remote termination is something they can do in the early boost phase, when there is a defined hazard zone over a depopulated patch of ocean. It doesn't cause the rocket to disappear; its effect is to disable the engines, end uncontrolled acceleration, and break the booster apart into small pieces—all of which will still fall to the ground (ocean) as debris.
If you did this to a Starship in orbit, you'd likely have large chunks of steel reentering and reaching the ground intact.
If I understand you correctly: So you'd have to do it over unpopulated/depopulated areas, which is impossible to guarantee when you are zooming around the globe at very high speeds. Thanks for explaining.
"...all of which will still fall to the ground (ocean) as debris..." After it's been flying in orbit for awhile, where it could in theory hit something else.
As you say, the other part of it--and probably more important--is that if it's turned into orbiting pieces, there's no control over where it lands. Some of it could easily land on the ground rather than the ocean, who knows where. That of course has happened with other satellites and their final stage rockets in the past (notably by the Chinese), but Starship is bigger, and therefore the pieces that hit the ground could be bigger. By launching it sub-orbital for now, and turning off the engines so it lands in the middle of the Indian Ocean, the risks of both orbital debris and unknown ground landing points are avoided.
If the object is already in orbit, the debris from an FTS activation would also mostly be left in orbit, which isn't great. They really need to demonstrate the ability to de-orbit the vehicle before putting into orbit.
Generally that isn't done for a vehicle in orbit, since the distribution of debris in orbits used by other spacecraft would be significant.
A Starship second stage stranded in orbit would be a problem because detonation would cause a bunch of orbital debris, but simply waiting for natural re-entry would result in an unpredictable landing location that could result in large debris reaching populated areas.
Reliable, controlled re-entry to a targeted location is very important for Starship to be an operational launch system.
It would work, all too well. Especially if the speed was just slightly suborbital. Rain of steel over a random spot (or, rather, a trace) on the Earth's surface. You may be lucky and that trace might cross a desolate ocean; or you may not be lucky, and some Asian megalopolis with 25 million people may be below.
Even at suborbital velocities, putting debris into the path of an existing satellite that is traveling at orbital velocity is enough to trigger a cascade.
No. An object in orbit colliding with anything threatens to create debris in orbit. Debris in orbit collides with other objects in orbit, creating debris in orbit. That's a cascade.
> Debris in orbit collides with other objects in orbit, creating debris in orbit. That's a cascade
For the same reason not every nucleus that fractures on neutron bombardment sustains chain reactions not every orbital configuration supports a Kessler cascade. In LEO, it’s virtually impossible: you get a nuisance, not SOL.
Note that Kessler posited his syndrome before we could computationally verify it. We can now. It’s not a real threat in the long term, and is more of an insurance question than existential issue for spaceflight in the medium term. It’s pertinent in the very short term, militarily, which is partly how we know it’s very difficult to trigger across even limited orbits.
LEO is the exact place you need to be careful. Higher orbits have more space and have fewer satellites overall so it's less of a concern.
Obviously not a problem for IFT6 since it's sub-orbital, but the original comment was about why we need a deorbit burn rather than just triggering the flight abort system.
> LEO is the exact place you need to be careful. Higher orbits have more space and have fewer satellites overall so it's less of a concern
No. In LEO orbits degrade in single-digit years at most. There is no known solution for rendering an orbit in LEO inaccessible with a Kessler cascade—the best you can do is blind an area with repeated ASAT fire.
In higher orbits debris last longer. That makes cascades possible, though again it only denies a limited area and requires almost active effort.
At least in LEO you need to keep expending DeltaV to keep stuff in orbit. Trace atmosphere slows everything down and would eventually clean LEO at 500km of relevant junk in about 25 years depending on altitude.
If you have debris in geostationary orbit, it will stay there basically forever whereas in low earth orbit it will burn up within a few years at worst.
Not to much mostly just a repeat. Just engine relight on the upper stage. The reason for this is that the next version is much improved and almost ready. That's the one they will really want to do the next steps with.
