Copyright 2016 Robert Clark
Blue Origin scored another first by successfully relaunching their vertical landing New Shepard suborbital rocket:
In the blog post "Triple Cored New Shepard as an orbital vehicle", I suggested using three cores of the New Shepard rocket with a small upper stage could form an orbital launcher. However Jonathan Goff on his blog page SelenianBoondocks raised the possibility a single New Shepard could serve as the first stage booster of an orbital rocket:
http://selenianboondocks.com/2016/01/random-thoughts-new-shepard-for-pop-up-tsto-nanosat-launch/
I think it should be doable using a similar small cryogenic upper stage as for the triple-cored case. The stage I suggested there was the cryogenic upper stage of the Ariane 4, the Ariane H10-3, or one developed by Blue Origin similar to it. It had a dry mass of 1,240 kg and a propellant mass of 11,860 kg. The Isp was 445 s with a vacuum thrust of 64.8 kN. However, simply using a nozzle extension as on the RL-10B-2 can give it likewise an Isp of 462 s and vacuum thrust of 110 kN. So we'll use these values.
To make the estimate of the payload we need the vacuum values for the Isp and thrust of the BE-3 engine. In the "Triple Cored New Shepard as an orbital vehicle" blog post I estimated these to be 360 s and 568.8 kN respectively.
However, to loft the vehicle with the additional weight of the upper stage we'll need to increase the BE-3 thrust slightly. This should doable. For instance the SSME’s could operate at 109% of their originally rated thrust, and the Merlin 1D had a 15% thrust upgrade. So say the BE-3 vacuum thrust is increased 9% to 620 kN, keeping the same Isp.
Now use Dr. John Schilling's payload estimator program. For the "Restartable upper stage" option check "No", otherwise the payload will be reduced. Select Cape Canaveral as the launch site and enter 28.5 for the launch inclination in degrees to match the latitude of the launch site. Then the calculator gives the result:
| Launch Vehicle: | User-Defined Launch Vehicle |
|---|---|
| Launch Site: | Cape Canaveral / KSC |
| Destination Orbit: | 185 x 185 km, 28 deg |
| Estimated Payload: | 1690 kg |
| 95% Confidence Interval: | 1298 - 2153 kg |
"Payload" refers to complete payload system weight, including any necessary payload attachment fittings or multiple payload adapters
This is an estimate based on the best publicly-available engineering and performance data, and should not be used for detailed mission planning. Operational constraints may reduce performance or preclude this mission.
Altitude Compensation to Increase Payload.
As I discussed in the "Triple Cored New Shepard as an orbital vehicle" blog post, altitude compensation provides a simple, low cost method of improving payload. For instance by attaching a nozzle extension the vacuum Isp of the BE-3 can be increased to the 462 s range of the RL-10B-2 engine. The vacuum thrust will then be increased proportionally to (462/360)*620 = 796 kN.
Then the Schilling calculator gives the result:
"Payload" refers to complete payload system weight, including any necessary payload attachment fittings or multiple payload adapters
This is an estimate based on the best publicly-available engineering and performance data, and should not be used for detailed mission planning. Operational constraints may reduce performance or preclude this mission.
Bob Clark
UPDATE, Feb. 28, 2016:
This considered an Ariane hydrolox upper stage as the upper stage for this New Shepard launcher. This would be problematical since it would be a direct competitor to Arianespace's Vega rocket at a much lower cost than the Vega's $35 million.
Blue Origin very likely could develop a hydrolox upper stage that would be cheaper than the Ariane one. But that would take time and significant development cost. Instead of that, Blue Origin could produce a New Shepard derived launcher for cubesats at minimal extra development cost since the required small upper stages already exist.
Existing upper stages that could work would be the large Star solid rocket upper stages such as the Star 63F:
Star 63F:
http://www.astronautix.com/engines/star63f.htm
Using this for the upper stage, Schillings launch performance calculator gives:
This is in the range being considered for the cubesat launchers that NASA has already awarded million dollar contracts to:
Firefly, Rocket Lab and Virgin Galactic Win CubeSat Launch Contracts from NASA.
By Caleb Henry | October 15, 2015 | Feature, Government, Launch, North America, Regional, Satellite TODAY News Feed
http://www.satellitetoday.com/launch/2015/10/15/firefly-rocket-lab-and-virgin-galactic-win-cubesat-launch-contracts-from-nasa/
Considering the quoted prices there, this New Shepard based launcher very likely could beat these prices especially using the reusable New Shepard.
And since the upper stage already exists, it very likely would also beat to launch these other systems still in development.
About the quick route to operational status of this orbital rocket, I think it is significant that Blue Origin was able to beat SpaceX on a relaunch of its returned booster. The argument has been made that New Shepard is not an orbital launcher. But if Blue Origin developed this orbital launcher from New Shepard then they would be able to beat SpaceX at reusing a booster for a true orbital launcher as well.
My opinion is SpaceX will have difficulty with getting their booster to land in reliable fashion as long as it does not have hovering ability. And because the New Shepard does have hovering ability it will be more reliable as a reusable booster.
BTW, as Blue Origin develops its large high performance dense propellant engines, it will have the same problem as SpaceX it getting its booster to be able to hover, resulting in the same problem of reduced reliability on landing. For this reason I think Blue Origin should investigate methods of giving its large planned boosters hovering ability such as discussed here:
Hovering capability for the reusable Falcon 9, page 3: hovering ability can increase the payload of a RLV.
http://exoscientist.blogspot.com/2015/12/hovering-capability-for-reusable-falcon.html
Surprisingly, it turns out that hovering ability when properly implemented can actually improve the the payload for a reusable rocket.
As I discussed in the "Triple Cored New Shepard as an orbital vehicle" blog post, altitude compensation provides a simple, low cost method of improving payload. For instance by attaching a nozzle extension the vacuum Isp of the BE-3 can be increased to the 462 s range of the RL-10B-2 engine. The vacuum thrust will then be increased proportionally to (462/360)*620 = 796 kN.
Then the Schilling calculator gives the result:
| Launch Vehicle: | User-Defined Launch Vehicle |
|---|---|
| Launch Site: | Cape Canaveral / KSC |
| Destination Orbit: | 185 x 185 km, 28 deg |
| Estimated Payload: | 2324 kg |
| 95% Confidence Interval: | 1841 - 2895 kg |
"Payload" refers to complete payload system weight, including any necessary payload attachment fittings or multiple payload adapters
This is an estimate based on the best publicly-available engineering and performance data, and should not be used for detailed mission planning. Operational constraints may reduce performance or preclude this mission.
Bob Clark
UPDATE, Feb. 28, 2016:
This considered an Ariane hydrolox upper stage as the upper stage for this New Shepard launcher. This would be problematical since it would be a direct competitor to Arianespace's Vega rocket at a much lower cost than the Vega's $35 million.
Blue Origin very likely could develop a hydrolox upper stage that would be cheaper than the Ariane one. But that would take time and significant development cost. Instead of that, Blue Origin could produce a New Shepard derived launcher for cubesats at minimal extra development cost since the required small upper stages already exist.
Existing upper stages that could work would be the large Star solid rocket upper stages such as the Star 63F:
Star 63F:
http://www.astronautix.com/engines/star63f.htm
Using this for the upper stage, Schillings launch performance calculator gives:
| Launch Vehicle: | User-Defined Launch Vehicle |
|---|---|
| Launch Site: | Cape Canaveral / KSC |
| Destination Orbit: | 185 x 185 km, 28 deg |
| Estimated Payload: | 293 kg |
| 95% Confidence Interval: | 174 - 443 kg |
This is in the range being considered for the cubesat launchers that NASA has already awarded million dollar contracts to:
Firefly, Rocket Lab and Virgin Galactic Win CubeSat Launch Contracts from NASA.
By Caleb Henry | October 15, 2015 | Feature, Government, Launch, North America, Regional, Satellite TODAY News Feed
http://www.satellitetoday.com/launch/2015/10/15/firefly-rocket-lab-and-virgin-galactic-win-cubesat-launch-contracts-from-nasa/
Considering the quoted prices there, this New Shepard based launcher very likely could beat these prices especially using the reusable New Shepard.
And since the upper stage already exists, it very likely would also beat to launch these other systems still in development.
About the quick route to operational status of this orbital rocket, I think it is significant that Blue Origin was able to beat SpaceX on a relaunch of its returned booster. The argument has been made that New Shepard is not an orbital launcher. But if Blue Origin developed this orbital launcher from New Shepard then they would be able to beat SpaceX at reusing a booster for a true orbital launcher as well.
My opinion is SpaceX will have difficulty with getting their booster to land in reliable fashion as long as it does not have hovering ability. And because the New Shepard does have hovering ability it will be more reliable as a reusable booster.
BTW, as Blue Origin develops its large high performance dense propellant engines, it will have the same problem as SpaceX it getting its booster to be able to hover, resulting in the same problem of reduced reliability on landing. For this reason I think Blue Origin should investigate methods of giving its large planned boosters hovering ability such as discussed here:
Hovering capability for the reusable Falcon 9, page 3: hovering ability can increase the payload of a RLV.
http://exoscientist.blogspot.com/2015/12/hovering-capability-for-reusable-falcon.html
Surprisingly, it turns out that hovering ability when properly implemented can actually improve the the payload for a reusable rocket.
4 comments:
(First version of this seem to got lost in DNS error a few days ago.)
Nozzle extensions arent magic. Adding extension to H10-3 or replacing it with RL10A-2 increases weight of the stage by 110kg.
I noticed that the only way I can replicate your result is to use 700kN as first stage thrust. With 620kN, the first figure you gave would be 1639kg.
Difference between using the first second stage engine and second would be then be 1447kg payload vs 1529kg. If using the same thrust, but the version of RL10 without extension still has 99kN. 10kN in this calculator makes 50kg difference.
Simmilarly with the first stage extensions arent massless. Sizing it up by thrust, it would add about 800kg to the first stage.
Furthermore its not deployed at sea level. According to tracking camera video of one launch of New Shephard vehicle, out of 140s thrust duration, it takes 60s to get to 10km/maxQ condition. So if that is the point where it should be deployed its at 45% of the thrust duration. Calculator is based mostly on time based equation, so the thrust and vacuum isp figures should be averaged 45/55.
Using extended first stage figures (14400kg 27300kg 720kN 416s) and extended second stage (1350kg 11860kg 110kN 462s) brings the payload to 1808kg.
So extending the second stage bell increases payload about 6%.
Extending first stage bell post significant atmosphere makes about 18% difference in itself. 25% using both.
Assuming Be3 has about 5:1 expansion, the 250:1 bell would be giant. Nearly 7m in diameter. Almost twice the diameter of the vehicle itself. Not sure about deployment at maxQ...
I was unfortunately using 28 instead 28.5 inclination. Doesnt change percentages, but final payload number would be 1864kg.
For the Schilling calculator be sure to enter 28.5 degrees as the launch inclination, even though in the results it's only listed as "28.0", to closely match the Cape Canaveral latitude. Also be sure to change the "Restartable upper stage" option from the default "Yes" to "No".
For mass of the nozzle extension, some of that is the extension mechanism not just the longer nozzle. If the nozzle is fixed with various adaptive alterations internal the mass should be less. There should also be lighter materials available now. I discussed some of these in the prior posts on the altitude compensation methods.
You may be right about the actual payload. Comparing to known rockets I estimate the Schilling calculator is about 10% accurate for the payload.
About the size of the extended nozzle for the BE-3 engine, perhaps we can make a comparison to the RL-10B-2 engine:
RL-10B-2
http://www.astronautix.com/engines/rl10b2.htm
Judging the size of the engine to be increased proportionally to the increase in thrust, each dimension would be increased by the cube root of 796/110, so by a factor of 1.93. This would bring the diameter to 1.93*2.13 = 4.11 m.
Still, my preferred embodiment of an altitude compensating attachment would be one that would be expandable from sea level to vacuum. That way you would not have the large drag increase due to having the large nozzle even at sea level air density.
Bob Clark
Im pretty sure engine thrust for the same chamber pressure, expansion ratio and isp, sizes proportionally to nozzle exit area. Not cube root of thrust.
Thrust is mass flow times exit velocity. Same exit velocity and pressure means thrust is proportional to area.
Or increase chamber pressure to decrease exit area for the same thrust in vacuum, or greater optimal expansion ratio at sea level.
Perfectly altitude compensated nozzle with low chamber pressure will always have less isp in atmosphere than high chamber pressure engine with optimal nozzle. Higher the pressure, less effect altitude compensation has on isp.
"The russian way" basically.
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