It is fair to say that there is no stage in space flight that can be considered simple. But that could be the case Most The hardest part of a spaceship journey is at the very beginning, within the first few minutes of takeoff. At the moment the car’s booster rocket will fight with all its might against its own huge propellant-loaded mass, a battle it is designed to win in the shortest distance. Assuming the balance has been hit correctly and the vehicle is out of the launch pad, accelerating it will still have to fight the dense ocean surface atmosphere, a building dynamic pressure that ends at a point known as “max q”. – The moment the air density imposes the maximum structural load on the rocket before it goes down quickly because the vehicle continues to climb and the atmosphere becomes thinner.
Although most rocket launches have to contend with the reality of flying through the lower atmosphere, there are some exceptions. By launching a rocket from an aircraft, it can avoid reinforcing itself from the sea surface. This allows the rocket to be smaller and lighter, as it does not require as much propellant and its engines do not need to be as powerful.
The downside of this approach, however, is that it requires a very large aircraft to carry even a relatively small rocket. For example, in order to place a 500 kg (1,100 lb) payload in orbit, Virgin Orbit’s Launcher One rocket must be launched at an altitude by a Boeing 747-400 aircraft.
But what if there was another way? What if you could get all the benefits of launching your rocket from a high altitude without the expense and logistical problems of carrying with a huge aircraft? This may sound impossible, but the answer is quite simple কঠিন all you have to do is work hard enough.
Getting Revved Up
This may sound like science fiction, but this is exactly what startup SpinLunch is currently doing in the New Mexico Desert. The plan is to use their mass accelerator, basically a vacuum-sealed centrifuge, to rotate a small rocket at 8,000 km / h (5,000 miles per hour). The car will feel up to 10,000 Gs before carefully departing at the specified moment which will allow it to exit the aerial centrifuge via a fast-acting airlock.
The rocket will then be coastal at an altitude of about 61,000 meters (200,000 feet), where it will ignite its first-stage engine. From that point the flight will proceed more or less like a traditional rocket launch, the payload will eventually accelerate to a nominal orbital speed of 28,200 km / h (17,500 miles). The big difference would be the cost, as SpinLaunch estimates the cost of each launch could be $ 500,000 USD.
Currently, SpinLaunch is conducting tests on a one-third scale centrifuge with a diameter of 33 meters (108 feet) and a simple high-speed airlock for a simple sheet of thin material that breaks its path when releasing test projectiles. Naturally this means that the centrifuge loses its vacuum after release, but that’s not really a problem at the start of the game; Maintaining a vacuum will only become important when the system is fully operational, and this is intended to help maintain a rapid launch cadence because the huge centrifuge chamber will not need to be pumped repeatedly.
So far they have flown passive projectiles at “thousands of feet” altitude, but it is far, far short of reaching orbit. The key to making this system work is to create a rocket that will not only withstand the huge G-force it can withstand when spinning at speed, but will also be able to guide itself to coast level before engine ignition using the control surface. Nor should it be said that this type of rocket has only one chance to get it right – if the engine of a traditional booster rocket fails to light at T-0, the launch can be scrubbed and the vehicle can be reconfigured to try again. But there is no work when the car is already flying in the air.
SpinLaunch seems confident that they can solve the engineering problems involved, but the fact remains that in the 1960s the United States and Canada undertook a similar project as a joint venture and things did not go exactly as planned.
Need for speed
The Technically High Altitude Research Project (HARP) began in the 1950s when ballistic engineer Gerald Bull took it upon himself that with a cannon large enough you would be able to shoot a payload directly into space. But someone familiar with Jules Verne From Earth to the Moon Knows that the idea is much older than that. Conceptually it makes sense to a certain extent, and it’s not that humanity hasn’t spent hundreds of years perfecting gunpowder weapons.
The HARP cannon was made by welding the barrels of a 16-inch naval gun together and mounted in such a way that it could be raised in a near vertical position. Barbados was chosen as the initial test site because its relative proximity to the equator would theoretically project projectiles thrown eastward to increase their velocity due to the rotation of the earth. Beginning in 1962, several launches were conducted that saw the Canadian-made Martlett fire a rocket cannon about 1,800 mm (70 inches) long.
Early flights carry research payloads that not only study the performance of the cannon, but also observe the condition of the upper atmosphere and near-space. The updated versions included solid rocket motors that were designed to ignite after the rocket was ashore for about 15 seconds in an effort to increase their speed and maximum altitude. The ultimate goal was to build a multi-stage rocket that could carry a small 23 kg (50 lb) payload at an altitude of about 425 kilometers (264 miles).
By the time HARP ended in 1967, the cannon had successfully launched more than 200 Martlet rockets, some of which had reached altitudes of up to 180 kilometers (112 miles). With a cost of just US 3,000 USD or roughly $ 27,000 per launch in 2022, it is one of the most affordable means of delivering a payload above the 100km Carmon Line, marking the internationally recognized boundaries of space.
Unfortunately, despite considerable effort, HARP has never been able to build a Martlet rocket that can successfully accelerate itself beyond the initial velocity fired from the cannon. For this reason, no rocket has been able to reach orbit, and return to Earth – often not far from the cannon.
The primary problem was the inability to build a rocket engine that could survive each rocket launch of 12,000+ g from cannon. So while HARP was technically a successful space launch program, it was limited to coastal research flights that became less scientifically valuable as more traditional rocket programs operated by NASA began to mature.
Explore new opportunities
Of course, the fact that HARP engineers did not design a rocket engine that could withstand high G-forces in the 1960s does not mean that SpinLunch cannot do it. This is hardly the first time a small startup has achieved something that the aerospace industry found impossible to enter. The company is also clearly aware of the challenge, as they recently released a video explaining that a large part of their research is now moving towards exploring the effects of the centrifuge environment on various rocket and spacecraft components.
But the truth is that there are many challenges ahead for SpinLunch. History tells us that the development of engines will not be easy, but there is really no precedent for the scale mass accelerators that have to be built to throw their car into the upper atmosphere. No one can ignore the fact that the cost of spaceflight is already declining rapidly due to commercial competition among suppliers such as SpaceX, Rocket Lab and Astra. A launch price of $ 500,000 would have been revolutionary 20 years ago, but not too far from where the market is heading today.
That said, all signs point to an exciting new era in space exploration ahead, and it’s not out of the question that Spinlaunch could find its greatest success from Earth. For example, it would be much easier to throw vehicles into orbit without an atmosphere like fighting a spin launch accelerator on the moon. Given NASA’s goal of establishing a long-term presence on and around the moon, the demand for a system that can lift payloads cheaply from the lunar surface may be high.
A small centrifugal satellite launcher mounted on a future space station can also be imagined to provide cubesat and other payloads with limited internal navigation. This may sound far-fetched, but keep in mind that the Japanese JM Small Satellite Orbital Deployer (J-SSOD) pushes the spacecraft out of their storage rack using a common spring-load mechanism currently used on the International Space Station. A small mass accelerator that allows the spacecraft operator to select the velocity and even the departure angle for their craft which will be a clear improvement over the current sophisticated conditions.
The fact of the matter is, we just don’t know what the future holds for SpinLunch. Their current technology showcase is impressive for what it is, but at the same time, it has moved so far from what will be needed to achieve their goals that it is hardly an indicator that the company is on the right track. Only time will tell whether others can succeed where they have failed, or whether they will join HARP as another interesting footnote in the long history of their mass accelerating spacecraft.