Author Topic: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)  (Read 1074265 times)

Offline shintoo

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2480 on: 06/29/2023 03:05 pm »
<snip />
Well, I'm not so sure. In the past there have been quite a lot of, admittedly rather out of date, renders of a Dreamchaser being launched off Roc. At the very least they at one point thought it was possible.

Here's a NASASpaceflight article about Dreamchaser on Roc from 2014:
https://www.nasaspaceflight.com/2014/10/dream-chaser-eyes-rides-with-under-review-stratolaunch-system/
Image bellow is the render from that time:
<snip />

I suspect that if you go with an all hydrolox launcher design, it might just barely be possible to build rocket that can launch Dreamchaser from Roc. It would certainly explain Stratolaunch's design decisions back when they were working on the PGA engine; it was a fuel-rich staged combustion hydrolox booster engine, about the size of Merlin 1D. Perfect for making your launch vehicle as light, when fueled, as can be managed. Please note that this is all purely vibes/it's-what-make-sense-to-me based. I haven't actually sat down and done the math for it.

Ah, I forgot about that concept, thanks for bringing it up again. It does, at the very least, show that they have been thinking about it for quite some time. I had assumed in my previous post that what they are currently considering is a horizontal takeoff for the "40% upscaled" (whether that is mass, volume, cargo capacity, I am not sure) crew-capable DC-200. As whitelancer64 pointed out, that version of DC being at 75% scale makes me less than hopeful that the much larger DC-200 could be launched by any sort of booster from underneath Roc. Still, I absolutely love that render.

<snip />
Note the rocket shown was called the Pegasus II, in development by Orbital (prior to their merger with ATK) in partnership with Stratolaunch. It was a 3 stage rocket, the first two stages were solid rocket motors, and the third stage was hydrolox, powered by one or two RL-10 engines. It had a payload capacity of 13,500 lb (6.1 metric tons) to LEO.

The DreamChaser to be launched was a 75% scale variant designed to be capable of flying 3 passengers or cargo.

Additional info: the Pegasus II solid rocket motors were the same diameter as the Shuttle SRB but had a carbon composite casing and a more energetic propellant mix. The first stage (which had two short wings and a V tail) was intended to be recoveable after splashdown.

The design was modified in late 2014 to use all solid rocket motors. However, the economic / business case for it never closed, so development was shelved, and later abandoned altogether.

Cheers for the great info on that project. I wasn't aware it was a scaled down version, that's really interesting. I suppose if DC had to be scaled down to launch under Roc, DC-200 launching under it is completely out of the question. I wonder if they are in discussions with Stratolaunch (or Scaled for a new aircraft?) for this new early-stage project with DC-200, if I'm not just plain wrong that Vice was referring to horizontal takeoff of DC-200. Certainly plenty of kinks to work out.

Online Lampyridae

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2481 on: 07/02/2023 10:03 am »
Sierra Space describes long-term plans for Dream Chaser and inflatable modules:
https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/

https://twitter.com/SpaceNews_Inc/status/1674017635472748546

I see they mention horizontal takeoff in the context of ending dependence on third-party launch vehicles...

Offline lrk

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2482 on: 07/05/2023 10:41 pm »
Sierra Space describes long-term plans for Dream Chaser and inflatable modules:
https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/

https://twitter.com/SpaceNews_Inc/status/1674017635472748546

I see they mention horizontal takeoff in the context of ending dependence on third-party launch vehicles...

 :o

Partnership with Stratolaunch?  Stratolaunch seems to be pivoting away from using Roc for Talon missions...

Online mn

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2483 on: 07/06/2023 03:12 am »
Sierra Space describes long-term plans for Dream Chaser and inflatable modules:
https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/

https://twitter.com/SpaceNews_Inc/status/1674017635472748546

Quote
As Sierra Space continues to prepare for the first flight of its Dream Chaser vehicle, it is outlining long-term ambitions for both that vehicle and space station modules
.

The headline says plans but the article more accurately describes it as ambitions.

Quote
We’re thinking about investigating the right technologies in thermal and propulsion and materials that allows us to potentially think about the staging options that would allow us, for the first time, have horizontal takeoff

My BS meter is way way up on this. I'm thinking of considering to investigate the possibility of believing any of this.

Offline shintoo

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2484 on: 07/06/2023 05:44 am »
Quote
As Sierra Space continues to prepare for the first flight of its Dream Chaser vehicle, it is outlining long-term ambitions for both that vehicle and space station modules
.

The headline says plans but the article more accurately describes it as ambitions.

Quote
We’re thinking about investigating the right technologies in thermal and propulsion and materials that allows us to potentially think about the staging options that would allow us, for the first time, have horizontal takeoff

My BS meter is way way up on this. I'm thinking of considering to investigate the possibility of believing any of this.

Especially when it's an investor conference... wild, oft unrealistic pitches seem to be a trend at those.

Let's root for 'em anyway. ;D

Offline Nomadd

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2485 on: 07/06/2023 09:21 am »
 I thought a loaded Dreamchaser was about twice the mass a Roc could orbit.
Those who danced were thought to be quite insane by those who couldn't hear the music.

Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2486 on: 07/06/2023 11:12 am »
This convo already occurred in another thread, but I can’t remember which one. It was based upon previous Stratolaunch pics. The net result of the discussion was that the spaceplane was somewhere in the neighborhood of 50 - 75% of the current Dream Chaser.

Offline whitelancer64

Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2487 on: 07/06/2023 04:59 pm »
Back in 2014 a 75% scale DreamChaser vehicle was envisioned to fly on Stratolaunch with a three-stage Pegasus II rocket. It would have held cargo or 2-3 people.

Stratolaunch is not likely capable of launching a full sized cargo DreamChaser, nor the larger crew variant planned.

Since neither could realistically fly on Stratolaunch, it stands to reason that this is something different.
« Last Edit: 07/06/2023 05:00 pm by whitelancer64 »
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Offline shintoo

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2488 on: 07/12/2023 06:16 pm »
https://www.nasa.gov/jsc/procurement/ccsc2

Quote from: Philip R. McAlister
For the Technical Approach evaluation, Sierra Space’s proposed technical approach demonstrated overall competence to achieving the proposed capability. Its capability concept received a significant strength for its integrated LEO transportation, destination, and infrastructure capabilities that utilize DC-200, Pathfinder, and other elements.

Emphasis mine.

What does Pathfinder refer to? Is that the name of the first DC-200 and I somehow missed that? Can't find any other references to the name. ???

Edit: It is certainly not the name of the first DC-200, not sure what to make of it. Emphasis mine.:
Quote from: Philip R. McAlister
For the Technical Approach evaluation, there was one new significant strength for engaging with industry partners for alternative transportation options to service Pathfinder and increase flexibility and availability of access.

« Last Edit: 07/12/2023 06:35 pm by shintoo »

Offline BrightLight

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2489 on: 07/12/2023 07:43 pm »
https://www.businesswire.com/news/home/20230615828732/en/Sierra-Space-Awarded-Space-Act-Agreement-with-NASA
"This SAA award by NASA provides support to a “pathfinder” space station, which serves as a technology demonstration for key elements of commercial space stations. Such demonstrations are vital steps to ultimately designing objects intended for sustained commercial habitation in orbit. The SAA is set to begin while the systems are in the design and development phases and last for five years – through on-orbit deployment later this decade."

https://www.nasa.gov/jsc/procurement/ccsc2

Quote from: Philip R. McAlister
For the Technical Approach evaluation, Sierra Space’s proposed technical approach demonstrated overall competence to achieving the proposed capability. Its capability concept received a significant strength for its integrated LEO transportation, destination, and infrastructure capabilities that utilize DC-200, Pathfinder, and other elements.

Emphasis mine.

What does Pathfinder refer to? Is that the name of the first DC-200 and I somehow missed that? Can't find any other references to the name. ???

Edit: It is certainly not the name of the first DC-200, not sure what to make of it. Emphasis mine.:
Quote from: Philip R. McAlister
For the Technical Approach evaluation, there was one new significant strength for engaging with industry partners for alternative transportation options to service Pathfinder and increase flexibility and availability of access.
« Last Edit: 07/12/2023 07:44 pm by BrightLight »

Offline shintoo

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2490 on: 07/12/2023 08:41 pm »
https://www.businesswire.com/news/home/20230615828732/en/Sierra-Space-Awarded-Space-Act-Agreement-with-NASA
"This SAA award by NASA provides support to a “pathfinder” space station, which serves as a technology demonstration for key elements of commercial space stations. Such demonstrations are vital steps to ultimately designing objects intended for sustained commercial habitation in orbit. The SAA is set to begin while the systems are in the design and development phases and last for five years – through on-orbit deployment later this decade."

<snip />

Thanks - I think the capitalization of "Pathfinder" threw me off.

Offline yg1968

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2491 on: 07/13/2023 03:33 am »
https://www.businesswire.com/news/home/20230615828732/en/Sierra-Space-Awarded-Space-Act-Agreement-with-NASA
"This SAA award by NASA provides support to a “pathfinder” space station, which serves as a technology demonstration for key elements of commercial space stations. Such demonstrations are vital steps to ultimately designing objects intended for sustained commercial habitation in orbit. The SAA is set to begin while the systems are in the design and development phases and last for five years – through on-orbit deployment later this decade."

<snip />

Thanks - I think the capitalization of "Pathfinder" threw me off.

Their space station is called Pathfinder:

Quote from: page 16 of the Source Selection Statement
While discussing Sierra Space’s proposal during the selection meeting, I noted that there are synergies with Orbital Reef, but enough differences that I see value in providing support to the development of Sierra Space’s Pathfinder station and DC-200 crew transportation system.

Online FutureSpaceTourist

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2492 on: 07/22/2023 06:59 am »
https://www.sierraspace.com/newsroom/blog/dream-chaser-vs-space-shuttle/

Quote
Dream Chaser vs Space Shuttle: A Side-by-Side Comparison
JULY 21, 2023   |   BLOG

When most people think of space travel, they likely think of space shuttles. What they don’t realize is that these were a specific type of reusable spacecraft only used by NASA from 1981 until 2011.

More than a decade ago today, on July 21, 2011, the last space shuttle mission landed at the legendary facility in the heart of Florida’s “Space Coast.” As Atlantis landed for the final time so too concluded the chapter in NASA’s 30-year shuttle program.

The historic runway at Kennedy Space Center has remained largely quiet since – for too long – as humanity lost the ability to return from space with a low-G runway landing and we bid farewell to an icon of spaceflight.

But that’s about to change.

Sierra Space is dedicated to bringing the Kennedy Space Center runway back to life and ushering in the next era of space exploration with its revolutionary fleet of Dream Chaser® spaceplanes.

The Dream Chaser is the first-ever winged commercial spaceplane, and although it looks somewhat like NASA’s space shuttle, it’s something entirely new. It’s also unlike Boeing’s X-37b, which exclusively conducts military missions, in that it will open shared access to space and international collaboration for all humankind

So, how does a Dream Chaser spaceplane vary from the traditional space shuttles we’re familiar with? Let’s explore the big differences.

Design and Configuration

NASA’s original space shuttle had a wing design much like an airplane. Instead of being independent and perched atop a rocket, it was integrated with an external fuel tank that provided fuel for its main engines and had two solid rocket boosters attached at the sides. Each space shuttle was designed to fly at least 100 missions – but they actually flew fewer than that.

The first model of the DC-100 cargo variant Dream Chaser is named Tenacity. Tenacity represents an uncrewed spiritual successor to the space shuttle, and at 30 feet (9 meters) long, it’s roughly a quarter of the total length of the space shuttle orbiters – though the habitable volume is about half the space shuttle.

The shuttle was 67 cubic meters (not including the airlock), and Tenacity’s pressurized volume is 33 cubic meters (including both the spaceplane and the cargo module). This makes the spaceplane more sustainable and easier to maneuver, but it also assists with gentle 1 g runway landings – ideal for fragile cargo.

Dream Chaser, Tenacity, was originally designed as a crewed spaceplane, partially under NASA’s Commercial Crew Program, before being awarded a NASA Commercial Resupply Services 2 contract. Under this contract, the Dream Chaser spaceplane fleet (including Tenacity), will provide a minimum of seven uncrewed cargo service missions to and from the International Space Station (ISS) and will be designed with high reusability in mind.

Launch and Reentry Procedures

Launching

Sierra Space Dream Chaser LaunchSpace shuttles were launched vertically on a launch pad, utilizing solid rocket boosters (SRBs) and main engines. Thus, shuttles needed 7.8 million pounds of thrust to reach orbit. The SRBs collectively provided 6.6 million pounds of thrust on top of the main shuttle engines, which added a total of 1.2 million pounds of thrust. The SRBs were jettisoned just after two minutes into the flight and the main engine cutoff would happen around eight minutes into the flight.

In comparison, Tenacity is compatible with a wide variety of launch vehicles (rockets) and will be launched in a stowed configuration inside a payload fairing. This makes Tenacity significantly more flexible and reduces ascent loads on the vehicle compared to the space shuttle.

With Tenacity in a payload fairing, it will sit on top of the rocket which will help protect the vehicle from debris. Sierra Space’s DC-200 crewed spaceplane variant will be launched in a similar configuration but without a fairing, which will still offer protection from debris since the rocket will be located below the vehicle.

Reentry

Back in the day, space shuttles executed controlled reentries into Earth’s atmosphere, entering nose-first at a high angle of attack to generate aerodynamic lift. Apollo astronauts were subjected to forces between 3-7 g’s though the shuttle missions saw less than 2 g’s on reentry.

As mentioned earlier, the Tenacity can return critical cargo to Earth at less than 1 g, contributing to a gentle and safe landing for the craft and its potential crew.

Of course, great leaps in tech don’t always happen smoothly. The Tenacity conquered tremendous challenges in its development, including early flight failures. Another big issue was figuring out how to demonstrate the spaceplane’s unique lifting body design ability to return to Earth with a smooth, low-G re-entry.

In 2017, Sierra Space conducted a pivotal test flight. NASA and other stakeholders needed to see that these capabilities were possible outside of computer simulations – so the Sierra Space team tested the hardware during a real, autonomously conducted atmospheric flight.

During the test, the spaceplane entered a 70-degree dive, quickly gaining airspeed to intercept its flight path for a normal Earth return. It performed flawlessly, autonomously deploying its landing gear, flaring, and touching down safely on a runway.
 
Payload and Capacity

Space shuttles had large payload bays that could carry a variety of cargo, including military and defense satellites, scientific instruments, and even entire space station modules. These payloads weighed up to 27,500 kilograms (60,600 pounds) in low-Earth orbit missions.

With the help of Sierra Space’s Shooting Star™ service module, the Tenacity spaceplane can deliver 5,500 kilograms (up to 12,000 pounds) of pressurized and unpressurized cargo to the space station before returning to Earth. Thanks to its internally developed thrusters with three different thrust modes, it can nimbly maneuver in space and ensure deliveries are effectively completed.

Although this payload is smaller, the spaceplane is highly customizable for a range of applications. The Tenacity is a multi-mission vehicle that can provide faster turnarounds and handle more lifetime loads.

Three separate NASA astronaut crews have visited the Sierra Space facilities to train on loading and unloading cargo in anticipation of Dream Chaser deliveries to the ISS.

The Future of Dream Chaser

The Dream Chaser fleet is multi-mission, capable of supporting a variety of low-Earth orbit needs and promising greater efficiencies with high reusability and fast turnaround times. Its customizability makes it ideal for domestic and international customers, as does its flexibility regarding launch site, space destination, mission duration, and landing site.

Tenacity will soon make its maiden voyage to deliver cargo to the ISS as part of its NASA CRS-2 contract. When it does, it will mark the beginning of a new era for space exploration globally (and beyond).

Learn more about Sierra Space and consider joining the team bringing about the Orbital Age TM.

Image captions:

Quote
Illustration of Sierra Space's Dream Chaser spaceplane on reentry

Quote
Sierra Space's Dream Chaser spaceplane landing on runway

Quote
Illustration of Sierra Space's Dream Chaser spaceplane cargo
« Last Edit: 07/22/2023 07:04 am by FutureSpaceTourist »

Offline Robert_the_Doll

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2493 on: 07/25/2023 07:58 am »
https://twitter.com/SierraSpaceCo/status/1683564642122235904

Quote
Before avionics were installed, the internal structure of Dream Chaser had visible gold composite of aluminum foil and other materials. This is used as a leakage liner to prevent oxygen from leaking out of the vehicle and maintain optimal pressure in the cabin.

Offline yg1968

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2494 on: 07/29/2023 08:25 pm »
Dream Chaser's Russian cousin:



Offline TrevorMonty

Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2495 on: 07/30/2023 10:21 pm »
Dream Chaser's Russian cousin:



More like anscestor. DC can trace its heritage to this vehicle via NASA attempts to copy it.

Russians would've been better off making BOR into small manned spaceplane than trying to copy NASA's Shuttle. Being able to land at runway is lot better than trying retrieve Soyzu from wilderness in Russian winter.
« Last Edit: 07/30/2023 10:30 pm by TrevorMonty »

Offline Steven Pietrobon

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2496 on: 08/02/2023 08:26 am »
More like ancestor. DC can trace its heritage to this vehicle via NASA attempts to copy it.

Russians would've been better off making BOR into small manned spaceplane than trying to copy NASA's Shuttle. Being able to land at runway is lot better than trying retrieve Soyuz from wilderness in Russian winter.

The true ancestor of Dreamchaser is the SV-5D PRIME lifting body, launched from 1966 to 1967 by the USAF! BOR is just a copy of PRIME.

https://space.skyrocket.de/doc_sdat/prime.htm
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline TrevorMonty

Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2497 on: 08/02/2023 11:39 am »
All stuff I read had BOR first, nice to know USA had idea first.
« Last Edit: 08/02/2023 11:40 am by TrevorMonty »

Offline adrianwyard

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2498 on: 09/03/2023 01:10 am »
Plenty of new info on crewed DC-200 in CCSC2 doc here:

https://www.nasa.gov/saa/domestic/38917_Sierra_Space_CCSC2_SAA-UA-23-38917_Baseline_signed.pdf

Notably: in-flight abort test in early 2026, so ~2.5 years from now. Pretty aggressive.

I'd really like to know why they chose to do a clean sheet design for the crewed vehicle rather than iterate. Perhaps adding comprehensive abort capabilities to current Dream Chaser required so many changes that clean-sheet was the easier path. But that's just a guess.
« Last Edit: 09/03/2023 01:19 am by adrianwyard »

Offline JAFO

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Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
« Reply #2499 on: 09/03/2023 06:07 pm »
All stuff I read had BOR first, nice to know USA had idea first.
You need to read this, then. From the original test pilot of the NASA lifting bodies (and X-15 pilot!), Milt Thompson. His X-15 book, At the Edge of Space, is also a fantastic read.


https://www.amazon.com/Flying-Without-Wings-Milton-Thompson/dp/0947554785
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