Orbital ATK introduces a new rocket
The competition heats up: Orbital ATK today revealed plans to build what it calls the Next Generation Launcher designed to compete with SpaceX’s Falcon 9.
The first stage would use a variation of the solid rocket boosters that ATK built for the space shuttle. The second stage would be bought from Blue Origin.
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
The competition heats up: Orbital ATK today revealed plans to build what it calls the Next Generation Launcher designed to compete with SpaceX’s Falcon 9.
The first stage would use a variation of the solid rocket boosters that ATK built for the space shuttle. The second stage would be bought from Blue Origin.
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
Rebirth of the Ares I? Maybe it will go better for them this time. Blue Origin looks interested in providing their services to whomever wants them and can pay for them. BO is getting involved in so many partnerships that one of them has to pan out eventually.
Use of solid rocket propulsion for first stage, despite its relative simplicity, is no way to obtain full reusability and an dead-end solution. Also its performance (Isp-wise, mass ratio ratio-wise) is much lover a liquid propellant first stage, so that a much larger first stage based on solid propellant (may be twice too heavy) has to be used. I would say let us use LH2/LOX for both stage, that allows due its superior Isp a much heavier and robust stage design compared to RP-1/LOX or methane/LOX-combination. The better reuse properties a hydrogen fueled vehicle counts more as cheaper RP-1/methane fuel and engines at the long run.
Alex,
I think that you are right that this is not a good long-term solution, but Orbital ATK is almost certainly looking for an inexpensive solution that they can incorporate quickly. The rocket engines are already designed and flight tested, and they can be reused with a known amount of refurbishment. Orbital ATK can design a better rocket later.
I suspect that the better long-term solution is a single stage to orbit (SSTO) rocket, such as Skylon:
http://www.reactionengines.co.uk/space_skylon.html
Although three versions of SSTO rockets were designed in the late 1990s, none made it past basic test phases. Each company failed to maintain funding to completion. The ratio of rocket structure to delivered payload is pretty poor for SSTO, but perhaps future materials and technologies can solve that problem.
If Skylon’s engine can be made to work (air breathing in the lower atmosphere, rocket the rest of the way to LEO), then they may have solved the payload problem.
Meanwhile, we are still trying to make a primitive 75-year old technology work for us at less cost.
I get this vision of Indigo Montoya saying “you keep using that word ‘compete’. I do not think that it means what you think it means”.
SpaceX already had the cheapest launch when throwing away the first stage. I don’t see how Orbital ATK will be competitive with a new throwaway while SpaceX is reusing the first stage.
Actually, right now I do not see how any of the established players, Arianespace, ILS, ULA, Orbital ATK, can compete. Even with their proposed newer rockets they are still more expensive than SpaceX’s expendable.Falcon 9. None come close to matching the price of the Falcon 9 with a reusable first stage, and none can compete with the Falcon Heavy in terms of payload and cost.
I expect the real competition to SpaceX will come from companies not yet established, like Blue Origin.
They just want to use the solid rockets because they already have them in production.
If any established company thought they were a better solution then they would already be using an all solid rocket first stage.
They keep trying to count in the estimated design cost and then subtracting the saving in using what they have already on the shelf.
That is like adding 100 years of automotive design and research into the cost of this years car and then subtracting that cost and saying we are getting a deal.
Wodun,
I don’t think Orbital quite has “Son of Corndog” in mind. Ares 1 used a four or five segment Shuttle/SLS-style SRB as a first stage. This new vehicle, I believe, is going to use twin-segment SRB’s as both first and second stages. The 3rd stage will use a vacuum-optimized version of Blue Origin’s BE-3. Using shorter solid boosters should reduce some of the acoustic problems Ares 1 had. Using an extra stage also improves the vehicle’s mass-to-orbit performance.
I think this rocket design is intended to extract the maximum value from marginal cost components. Orbital-ATK is already committed to making SRB segments for SLS SRB’s. But if SLS only flies every other year, Orbital will only be making them at a five-per-year average rate. Selling even one of these new rockets per year nearly doubles the production rate of SRB segments as the new rocket needs four of them.
Using the BE-3 for the upper stage is good because Blue Origin will realize at least a bit of average cost reduction on an engine already in production and use. Finally, Orbital already has a USAF contract to put a vacuum-optimized engine bell on the BE-3 so Uncle Sugar is picking up the tab for a significant fraction of the total development expense for this new vehicle.
I still think beating SpaceX is probably out of the question, but this vehicle still might get some takers. They are likelier to be at ULA’s expense than SpaceX’s though.
Alex,
LOX-LH2 1st stages have proven, in practice, to be sub-optimal because the vehicle has to be so much bigger and heavier to accommodate the LH2 tankage and the Isp hit for sea level versus vacuum operation is greater for LOX-LH2 than for other propellants. The SSME, for instance, gave away over 85 sec. Isp at sea level. The LOX-RP1 Merlin 1-D, in contrast, gives away less than 30 sec. Isp. This makes LOX-LH2 disproportionately better as an upper stage propellant combo, while LOX-RP1 is superior, overall, in 1st stage applications.
Edward,
The rocket equation is no friend of pure rocket SSTO for Earth orbit applications. The “cheat” Skylon embodies in using atmospheric oxygen would seem to pay its greatest dividends in the lower atmosphere. I’m open-minded about how light Reaction Engines can make the extra bits needed for their SABRE engine vs. a pure rocket, but I think even a reasonably successful Skylon SSTO could be easily beaten with respect to overall economy by a two-stage craft that uses the SABRE engine technology in a fly-back 1st stage and a pure rocket in the upper stage. Just like the sword for which it is named, SABRE has two edges. One, perhaps, enables an SSTO Skylon with a greater-than-token payload capacity. The other enables a two-stage alternative that beats hell out of Skylon in kg. to orbit for a given propellant load and comparable or lower vehicle cost.
Dick: The “loss in Isp” (in comparison of sea level to vacuum) that you mentioned does not depend from chosen propellant as you have proposed, but practical only from engine parameter as chamber pressure and nozzle expansion ratio. The SSME parameter are optimized for a higher average application altitude as the Merlin-1D engine. You would find even a large “Isp reduction” in case of Merlin’s vacuum version. There is also another misconception in your comment: The mass contribution of LH2 tankage is not so large as you may imagine. It may be in the order of 10% of total vehicle’s structural mass. BTW, the typical large diameter of LH2 fueled vehicle has a positive side effect. The vehicle becomes more effective decelerated in atmosphere by reentry, with less thermal load.
Dick,
I don’t consider Skylon as much of a “cheat” but rather as a solution.
I also would not consider a space elevator as a cheat but as another solution. However, I think that space elevators come with some problems that may be difficult to overcome.
Alex,
I have been looking all week for answers by a rocket scientist or engineer as to why RP-1 or other hydrocarbons are used in rocket first stages rather than LH2 (I am not an actual rocket scientist; I just play one on the internet — I used to build satellites and design and build scientific space instruments for satellites). The best I could find is something that matches my understanding of the problem: during the boost phase, thrust is more important than efficiency.
At this link, Phil Karn’s answer best matches what I have learned over the years.
https://www.quora.com/Why-did-they-use-kerosene-as-the-propellant-in-the-first-stage-of-the-Saturn-V-and-liquid-hydrogen-in-the-upper-stages
Here is a passage from page 254 of the 6th edition of “Rocket Propulsion Elements” by George Sutton, who had 45 years of experience in rocket propulsion, at the time of publication.
“Some studies have shown that when burned with liquid oxygen, a hydrocarbon (such as methane or RP-1), can give a small advantage in space launch vehicle first stages. Here the higher average propellant density allows a smaller vehicle with lower drag, which compensates for the lower specific impulse of the hydrocarbon when compared to a hydrogen fuel. Also, there are some concepts for operating the booster-stage rocket engine initially with hydrocarbon fuel and then switching during flight to hydrogen fuel. As yet, engines using two fuels, namely methane (or hydrocarbon) and hydrogen, have not yet been developed or flown.”
My understanding of the problem has been that energy management is important in rocketry. What is the best use of the available energy, and what makes for the least overall propellant usage. As in much of rocketry and space travel, sometimes the answers are counter-intuitive.
As you probably already know, higher propellant mass efficiency (specific impulse) comes from higher propellant velocity; the energy imparted into the propellant is proportional to the mass and the square of the velocity; and the force exerted is proportional to the mass flow rate and the velocity (no square). Above some velocity, more energy is put into increasing the propellant’s velocity (increasing Isp) than into increasing the thrust.
Since thrust on a planet’s surface is the priority, giving more acceleration early in the launch, using the engine’s energy on thrust can take precedence over efficiency and prove to be more fuel efficient in the overall launch. This requires increasing the mass flow rate rather than the velocity, and since increasing the flow rate by increasing the combustion chamber pressure would likely over stress the engine, a higher molecular weight of the exhaust would be desirable. Hydrocarbons supply the heavier CO2. (If combustion is incomplete, then most of the unburned carbon, or soot, would also be heavier than H2O.)
I like to think of a slow launch as “hovering,” where propellant is used to counter gravity and not to accelerate. A rocket that leaps off the pad and quickly accelerates uses less overall fuel while fighting gravity, although at some point it spends too much to fight air resistance. Obviously, there are plenty of trade-offs necessary during rocket design.
Of course, once high enough and fast enough, the rocket is no longer in imminent danger of hitting the ground and can use lower thrust but higher efficiency engines to achieve orbit or escape velocity.
The importance of thrust over Isp during the boost phase, at least on Earth, can be seen by the use of solid rocket boosters. Solid rockets use heavier propellants, thus their Isp tend to be lower than if they used H2/LOX (although, I agree with you that they are a dead-end solution).
Clearly, there is a gravity-strength below which H2/LOX would be more efficient in launching vertically from a gravity well, but the Earth’s gravity seems to be above that point. I like the solutions that Skylon and XCOR proposed, flying from a runway and using the efficiency of a wing to gain initial altitude. Skylon even uses H2 as a fuel.
Edward:
Fascinating stuff!
What is the main appeal of using old ICBM engines?
“What is the main appeal of using old ICBM engines?”
I don’t have knowledge of the reason, but I suspect it is because they exist (low cost/AF gets to recover some construction cost) and the design works. However, as we learned with the Russian NK-33 engine (redesignated AJ26, after refurbishment for use on Orbital’s Antares launch vehicle), this is not always a guarantee of reliability.
If you haven’t seen it yet, this one-hour documentary discusses how the NK-33 were designed for the Russian moon rocket and stored for a few decades before Aerojet decided to sell them and Orbital bought them to launch satellites. The latter part discusses the use of the Russian RD-180 on the Atlas V launch vehicle.
https://www.youtube.com/watch?v=TMbl_ofF3AM
Edward: Very interesting video. (The Engines That Came In From The Cold)