Test results from NASA saucer Mars landing test
NASA has released video and test results from the first test flight of its Low-Density Supersonic Decelerator (LDSD), referred by many press outlets as a “flying saucer” because of its shape.
The purpose of the test was to see if the saucer and its parachute would work to slow a vessel down sufficiently in the Martian atmosphere. The parachute tore and failed. The video describes the flight and the failure and how the data from this failure can now be used to modify the parachute for the next two test flights.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
NASA has released video and test results from the first test flight of its Low-Density Supersonic Decelerator (LDSD), referred by many press outlets as a “flying saucer” because of its shape.
The purpose of the test was to see if the saucer and its parachute would work to slow a vessel down sufficiently in the Martian atmosphere. The parachute tore and failed. The video describes the flight and the failure and how the data from this failure can now be used to modify the parachute for the next two test flights.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
I saw a documentary on the development of the parachutes for Spirit and Opportunity which experienced similar failures during development. Getting delicate parachutes to reliably open at supersonic velocities is a very tricky business. Particularly as the mass of the payload increases. In some ways, it seems harder than rocket science. :-)
Seems like a relatively poor engineering choice to demand supersonic deployment and decel out of the parachutes.
I’m sure the smart engineers at JPL / Hughes have looked at the trade of weight of fuel for propulsive decel vs. parachute weight.
Even if propellent weight is a bit more, it could easily end up being much, much less expensive, and much, much less risky to use propulsive decel.
I recall hearing several JPL employee declare that it was “impossible” to use propulsive decel in the atmosphere during entry. This has now been proven incorrect by the F9R.
Couldn’t they just throw their junk at <ars at a slower speed and wait a little longer?
Then the entry speed might just be a little slower.
There is a minimum entry speed determined by the speed of an object that falls from infinity. My quick calculation shows that at Mars it would be somewhere around 750 meters per second, which is still pretty fast for a parachute. So even if the approach to Mars were very slow, the reentry speed would still be fast.
That is why Fred K suggested using rockets to slow the craft before reentry or before parachute deployment.
Now that you mention it, I noticed that JPL stopped using Hohmann Transfer Orbits to get to Mars (minimum energy required to reach the second orbit). This transfer orbit would reach Mars orbit, but the spacecraft would be travelling much slower than Mars, making for a large relative velocity. Does anyone know whether JPL’s modern, faster transfer orbit results in a lower relative velocity between the spacecraft and Mars?
I also think that Fred may be in error about Falcon 9 showing that rockets can be used during reentry, because Falcon 9 didn’t exactly reenter from orbit but from a suborbital trajectory. It didn’t go through a dramatic, ionizing, heat-shield-requiring, hard-to-fire-your-retrograde-rockets reentry.
Falcon ( is suborbital.
Its their second stage that they are thinking of recovering from an orbital speed. But I don’t think they have finalized any plans or designs on it yet.
And for NASA’s new parachute system to work it has to get the chute out of the unstable wake of the in falling craft.
Which should just mean a linger tether.
But since the basic idea of an inflatable braking system does tend to work what if they reshapped it to form a lifting body and gave the craft a little control for the possibility to stay up in the atmosphere for a longer period. Thus shedding more speed before the chute deploys for landing.