Dragon capsule parachute test

On 8/22/2010 2:31 PM, Eddie Lyons wrote:


Why not make the assumption that Dragon would be as capable of landing under
adverse conditions as Soyuz is? There have been very few occasions when a
Soyuz departure from Salyut, Mir or ISS has been delayed because of weather
conditions, or targeted at a back-up landing area. Surely the American
southwest is big enough to be able to provide more than one landing area?


I always got a kick out of a water landing in The Great Salt Lake. The
weather never gets that bad on it, and due to the high density of the
highly saline water, the capsule would bob around like a cork.

Pat

On Aug 21, 9:47*pm, David Spain wrote:
Sylvia Else wrote:

Land somewhere else?

Sylvia.

Doesn't anyone sleep around here, or do you all live on the Left Coast or
Asia?

Droll Sylvia... Care to clue us in as to 'where' else is?
Central Park in Manhattan?

The other option is also to stay in orbit longer...

Dave

Or better yet is for them to go rogue so that we don't have to
continue paying.

~ BG

On Aug 21, 9:43*pm, Sylvia Else wrote:
On 22/08/2010 2:41 PM, David Spain wrote:

Pat Flannery wrote:
Unlike Orion, Dragon's parachutes actually work:
http://www.onorbit.com/node/2431

Pat

Says they are starting with water 'splashdowns' for the crewed version
with the intension of moving to land 'dustdowns' with addition of
deployable landing gear and thrusters at some point in the future.

That should help reduce costs. What are their landing options in case of
bad weather at the primary landing site?

Dave

Land somewhere else?

Sylvia.

Since they're flying on human blood as their fuel and everything else,
they get to land anywhere they like, as well as they get as many do-
overs as they like.

~ BG

David Spain writes:

Pat Flannery wrote:
Unlike Orion, Dragon's parachutes actually work:
http://www.onorbit.com/node/2431

Pat

Says they are starting with water 'splashdowns' for the crewed version
with the intension of moving to land 'dustdowns' with addition of
deployable landing gear and thrusters at some point in the future.

I fear this will happen shortly after they start to routinely recover
both first and second stages of the Falcon 9...

I really don't see why they should even try that. It surely adds quite a
bit of mass which comes straight out of the payload and the time/cost
savings would only be significant if they fly very often.


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery

On 23/08/2010 1:09 AM, Jochem Huhmann wrote:
David writes:

Pat Flannery wrote:
Unlike Orion, Dragon's parachutes actually work:
http://www.onorbit.com/node/2431

Pat

Says they are starting with water 'splashdowns' for the crewed version
with the intension of moving to land 'dustdowns' with addition of
deployable landing gear and thrusters at some point in the future.

I fear this will happen shortly after they start to routinely recover
both first and second stages of the Falcon 9...

I really don't see why they should even try that. It surely adds quite a
bit of mass which comes straight out of the payload and the time/cost
savings would only be significant if they fly very often.


The time and cost savings go straight to the bottom line of each launch.
It's the development costs that need to be justified by launch rates.

Sylvia.

According to this strategypage article on the USAF's
GPS-guided parachute system:

http://www.strategypage.com/htmw/htairmo/20070529.aspx

"bringing the pallet (with up to five tons of supplies) down within a
hundred meters of the programmed landing point."

If you can parachute-drop something that accurately, you can just
dig a pond in the landing area if you want a water-cushioned
landing.

On 23/08/2010 12:29 PM, wrote:
According to this strategypage article on the USAF's
GPS-guided parachute system:

http://www.strategypage.com/htmw/htairmo/20070529.aspx

"bringing the pallet (with up to five tons of supplies) down within a
hundred meters of the programmed landing point."

If you can parachute-drop something that accurately, you can just
dig a pond in the landing area if you want a water-cushioned
landing.

Well...

100 metres radius, and say 2 metres deep. That's 62 thousand tonnes of
water. You're not going to truck it in, which limits your choice of
location.

Sylvia.

On 8/22/2010 6:29 PM, wrote:
According to this strategypage article on the USAF's
GPS-guided parachute system:

http://www.strategypage.com/htmw/htairmo/20070529.aspx

"bringing the pallet (with up to five tons of supplies) down within a
hundred meters of the programmed landing point."

If you can parachute-drop something that accurately, you can just
dig a pond in the landing area if you want a water-cushioned
landing.

Although simply letting it float under the influince of the winds from
high altitude wouldn't work in this regard, popping the main chutes at
around 500-1,000 feet altitude would let you put it down with that
degree of accuracy; partiulary if weather conditions were taken into
account during its reentry to put it dead over the middle of the landing
site before the chutes opened at very low altitude.

Pat

Sylvia Else wrote:
On 23/08/2010 1:09 AM, Jochem Huhmann wrote:
I fear this will happen shortly after they start to routinely recover
both first and second stages of the Falcon 9...

I really don't see why they should even try that. It surely adds quite a
bit of mass which comes straight out of the payload and the time/cost
savings would only be significant if they fly very often.


The time and cost savings go straight to the bottom line of each launch.
It's the development costs that need to be justified by launch rates.

So one observation: if they are going to the trouble to perform water recovery
on the first and second stages then the infrastructure for water recovery is
fixed in the cost of operation. Adding water recovery for the capsule would be
a small delta increase given this.

I'm speculating that the biggest driver in the cost to recover (the capsule)
is the accuracy of the landing in terms of how close to the launch point this
can be. Assuming a reusable capsule, getting it back as close to the LP as
possible can only help to reduce the cost of handling and reprocessing.
Putting it down on land can only help. However, if the infrastructure for
water recovery of the stages is already there then it becomes less clear.
Maybe water recovery on the Indian/Banana[1] River or in the Atlantic near the
Cape would be sufficient and help keep the capsule simple.

Begs the question of why this wasn't done in earlier manned programs.
I assume if you start from the point of view of a disposable capsule it isn't
as important to consider the landing point. Mercury, Gemini and Apollo weren't
exactly based on cost-of-operation amortized over flight rates. SpaceX
operations are inherently different in this regard and will be a uniquely 'new
thing' about this program, with little prior art. That plus we won't be
re-tasking a carrier fleet each time we need to perform a crew recovery.

This, to me, is the most interesting aspect of the SpaceX program. And one I
will follow closely.

Dave

[1] With the Banana River a designed Aquatic Preserve it would probably be too
tricky to get authorization to conduct recovery ops there, whilst the Indian
River has causeways (actually they both do) that presents hazards. Looks like
the best bet would be to drop into the Atlantic just east of the the Bight and
recover and ship west to the channel at the southern end of the Bight into the
Air Force Station.

Have to consider if the coastal waves in the Atlantic get to be too rough
there. Having experienced both first hand I've noticed there is significant
difference between seas in the Atlantic on the east coast of Fla, vs those of
the Gulf on the west side.

http://www.dep.state.fl.us/coastal/d...aps/banana.pdf
http://tinyurl.com/29joqac

On 23/08/2010 12:35 PM, David Spain wrote:
Sylvia Else wrote:
On 23/08/2010 1:09 AM, Jochem Huhmann wrote:
I fear this will happen shortly after they start to routinely recover
both first and second stages of the Falcon 9...

I really don't see why they should even try that. It surely adds quite a
bit of mass which comes straight out of the payload and the time/cost
savings would only be significant if they fly very often.


The time and cost savings go straight to the bottom line of each
launch. It's the development costs that need to be justified by launch
rates.

So one observation: if they are going to the trouble to perform water
recovery on the first and second stages then the infrastructure for
water recovery is fixed in the cost of operation. Adding water recovery
for the capsule would be a small delta increase given this.

It may just be a development timescale issue. They can test much of the
reentry hardware now without waiting for landing gear development and
testing, which can thus proceed in parallel.

I'm speculating that the biggest driver in the cost to recover (the
capsule) is the accuracy of the landing in terms of how close to the
launch point this can be. Assuming a reusable capsule, getting it back
as close to the LP as possible can only help to reduce the cost of
handling and reprocessing. Putting it down on land can only help.
However, if the infrastructure for water recovery of the stages is
already there then it becomes less clear. Maybe water recovery on the
Indian/Banana[1] River or in the Atlantic near the Cape would be
sufficient and help keep the capsule simple.

It appears they propose to pick the capsule from the water using a
helicopter and carry it to land. It's not clear whether that would be
acceptable with a crew inside. If you have to get the crew out first,
then everything becomes more complicated. Also, if you're going to do
water landings with a crew, then you presumably need to have a life
raft, etc, which you don't need for landings on land.


Begs the question of why this wasn't done in earlier manned programs.
I assume if you start from the point of view of a disposable capsule it
isn't as important to consider the landing point. Mercury, Gemini and
Apollo weren't exactly based on cost-of-operation amortized over flight
rates. SpaceX operations are inherently different in this regard and
will be a uniquely 'new thing' about this program, with little prior
art. That plus we won't be re-tasking a carrier fleet each time we need
to perform a crew recovery.

I dare say that sea landings were seen as the safest option when money
was no object.

Sylvia.