Dream Chaser vs Space Shuttle: A Side-by-Side Comparison

Illustration of Sierra Space's Dream Chaser spaceplane on reentry

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 1.5 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 <span class=Space 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 1.5 g’s, 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.

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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.

Illustration of Sierra Space's <span class=

 

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®.

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