The next SpaceX Falcon Heavy launch takes place tonight, Monday, June 24, around 11:30 p.m. EDT, from NASA's historic Pad 39A at the Kennedy Space Center in Florida. The Air Force Space Test Program-2 (STP-2) mission will deploy 24 science and technology demonstration satellites for NASA, NOAA, DoD research laboratories, and the Planetary Society.
The launch time has been moved to 2:30 a.m. EDT.
This will be the first time the Falcon Heavy will employ previously used first-stage side boosters; these were recovered from the Arabsat 6A mission on April 11 this year. As in the Arabsat 6A mission, the two side boosters will land at KSC, the center booster will attempt a landing on the drone ship Of Course I Still Love You, stationed ~1,240 km out at sea. Fairings recovery will also be attempted using the ships GO Ms. Tree and GO Navigator, located even farther out.
The launch will be webcast at the NASA Television website, the SpaceX website and YouTube. The night-time launch and landings promise to produce some spectacular viewing and images.
Here is a look at the bevy of payloads stacked inside the nose cone of the rocket.
Here is a picture of the Falcon side boosters hanging in the hangar (!) at KSC and a video of the launch of the Arabsat-6A mission on April 11 with the twin boosters making a perfect synchronized landing.
Launch Overview
This challenging launch mission will include four separate upper-stage engine burns, three separate orbits where satellites are deployed, a final propulsive passivation maneuver, and a total mission duration of over six hours. Watch the animation below for a look at the various stages of the launch and satellite deployment.
The “propulsive passivation maneuver” in the video looks like a pressurized ejection of leftover fuel without burning it.
NASA/NOAA Payloads
The spacecraft will carry 4 science payloads for NASA and a set of 6 weather satellites for NOAA.
- The Deep Space Atomic Clock (DSAC) is a test and demonstration of a toaster-size atomic clock, that will be used to guide future deep-space missions. Atomic clocks combine a quartz crystal oscillator with an ensemble of atoms to achieve the high stability required to precisely measure distances to distant spacecraft. DSAC’s time-keeping will be off by only a nanosecond after 4 days, similar to ground based refrigerator sized atomic clocks. For inter-planetary missions, such precision makes autonomous navigation possible with minimal communications with Earth — a significant improvement over current spacecraft navigation methods.
- The Green Propellant Infusion Mission (GPIM) is a demonstration of a “green” propellant called AF-M315E, a non-toxic, hydroxyl ammonium nitrate based, rosé-colored liquid, that is safer to handle than hydrazine and has 50% higher performance. The European Union is even considering a ban on the use of hydrazine as early as 2021, due to its toxicity.
- The Space Environment Testbeds (SET), which consists of four small spacecraft to study how spacecraft electronics respond to space radiation. Energetic particles from the Sun or deep space can flip memory bits in on-board computers, and over time, degrade electronics. SET seeks to better understand these effects in order to improve spacecraft design, engineering, and operations. The study will target the “slot” region located between the inner Van Allen Belt (1,000 km to 6,000 km) and the outer one (13,000 to 60,000 km). The doughnut-shaped Van Allen belts seethe with radiation trapped by Earth’s magnetic field.
- The Enhanced Tandem Beacon Experiment (E-TBEx) will study bubbles in the ionosphere, which can disrupt communications and GPS signals. A pair of small cubesats will transmit precise signals at several frequencies that will be recorded on the ground. E-TBEx mission will work in concert with six NOAA's COSMIC-2 satellites which carry similar beacons and which are also part of this launch.
- The Constellation Observing System for Meteorology, Ionosphere, and Climate-2 (COSMIC-2) will be a network of six remote-sensing micro-satellites, which, from its medium earth orbit location, will collect atmospheric data used for weather forecasting, climate monitoring, and space weather research.
Here are a few videos and images of the NASA/NOAA missions.
LightSail 2
One of the most exciting and much anticipated payloads is the crowdfunded LightSail 2 spacecraft, designed by the Planetary Society. It aims to become the first spacecraft in Earth orbit propelled solely by sunlight. The technology can be used as a means of propulsion for near earth orbit CubeSats as well as for inter-planetary spacecraft.
LightSail 2’s sail is a modest 32 square meters in size and is intended for test and demonstration.
Here is an overview of the LightSail mission.
Yes, that is how small the LightSail 2 apparatus is, with the light sail neatly tucked inside the enclosure, known as Prox-1, designed by a student team from Georgia Tech. (During launch, the solar panels seen below will be folded along the sides of the “breadbox.”)
Key LightSail 2 Parameters
Parameter |
Value |
Spacecraft weight |
5 kg |
Spacecraft size |
11.3 x 11.3 x 48.7 cm |
Sail area |
32 square meters |
Sail material |
Mylar |
Sail thickness |
4.5 microns (less than the width of a human hair) |
Light Force |
0.0001 Newtons
For comparison, the Falcon Heavy first stage produces 22,189,000 Newtons of thrust (934,000 Newtons for the 2nd stage)
|
Acceleration |
0.058 mm/s2 |
Initial altitude |
720 km |
Expected altitude increase |
0.5 km per day |
Mission duration |
1 month; will coast and re-enter atmosphere after around 1 year |
Ground stations |
Kauai Community College, Cal Poly San Luis Obispo, Purdue University, and Georgia Tech. |
Call sign |
WM9XPA |
Project cost |
$7 million, from 2009 through March 2019 |
Solar Sailing
Solar sails are, in principle, similar to sails used in sail-boats. When light impinges on a solar sail — which has a bright, mirror-like surface — photons, which have no mass but carry momentum, transfer their momentum to it, giving it a small push. The net force is quite small, but in the vacuum of space, this radiative push, accumulated over several weeks and months can make a big difference in the velocity of a spacecraft, without the use of any chemical based propellant, which itself must be carried into space using heavy rockets. See www.planetary.org/… for more details.
Note that solar sails do not use the “solar wind” which is composed of ions ejected by the Sun and which in aggregate carry lot less momentum than solar light.
Here is Bill Nye explaining solar sails in his own inimitable way -
LightSail 2 Mission Timeline
From www.planetary.org/… — The Prox-1 and LightSail 2 spacecraft will be delivered into a circular, 720-km orbit with an inclination of 24 degrees.
After a checkout period of a few days, LightSail 2 will open its hinged solar arrays. About a day later, it will unroll 4 cobalt-alloy booms, which will extend like tape measures to pull the spacecraft's 4 triangular sails from storage. The deployment sequence will take roughly 3 minutes.
LightSail 2 will then begin swinging its solar sail into and away from the Sun's rays as it circles the Earth, giving the spacecraft enough thrust to raise its orbit. This portion of the mission will last 1 month. Watch the animation below to understand how the sail orientation is adjusted in orbit to catch the light and increase its speed -
LightSail 2's attitude control system does not have the precision to maintain a circular orbit and continuously fly the spacecraft higher. Therefore, as one side of LightSail 2’s orbit rises, the other side will dip lower, until atmospheric drag overcomes the forces of solar sailing, ending the primary mission. The spacecraft will remain in orbit roughly a year before entering the atmosphere and burning up.
Watching LightSail 2
LightSail 2 may be visible to the naked eye after solar sail deployment. Once the sails are out, the Planetary Society will post a dashboard offering pass predictions for any location.
The spacecraft will have an orbital inclination of 24 degrees, which will restrict viewing to latitudes within 42 degrees of the equator.
The History of Solar Sailing and The Planetary Society
The concept of solar sails go back several centuries with many scientists contributing to its understanding and design. Johannes Kepler observed that comet tails point away from the Sun and suggested that the Sun caused the effect. In a letter to Galileo in 1610, he wrote, "Provide ships or sails adapted to the heavenly breezes, and there will be some who will brave even that void." See en.wikipedia.org/… for a description of the history of solar sails.
The Planetary Society was founded in 1980 by Carl Sagan, fellow NASA scientist Bruce Murray, and engineer Louis Friedman. Today, it continues the work, under the leadership of CEO Bill Nye, as the world’s largest and most influential non-profit space organization. The organization is supported by over 50,000 members in over 100 countries, and by hundreds of volunteers around the world.
Sagan (and Murray) was a proponent of using solar sails for space propulsion, and spoke about it with unbound enthusiasm, much to the delight of viewers of the Johnny Carson show.
The Society’s goal has been to promote and advocate for space exploration, and got expanded to development and demonstration of space technologies. Solar sailing was one of the technologies that the Planetary Society has focused on since interest from NASA and other organizations waned over time.
In 2005, the society launched the world’s first solar sailing spacecraft, Cosmos 1, which was lost due to a rocket failure. Ten years later in 2015, the LightSail 1 spacecraft successfully completed a test flight. This week, we will see the much anticipated deployment of LightSail 2.
IKAROS
In 2010, the Japanese IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) spacecraft used solar sailing to reach Venus. It was the first spacecraft to successfully demonstrate solar sail technology in interplanetary space. The 196 m2 solar sail included thin-film solar cells integrated into the sail for power and 80 liquid crystal panels whose reflectance was varied to perform attitude control.
LightSail 2 has a tougher job to do, physically re-orienting its sail by 90 degrees twice per orbit.
The Future of Solar Sails
There are no plans for LightSail 3. The technology will be passed on to NASA and other space organizations.
NASA’s Near-Earth Asteroid Scout (NEA Scout) mission will use a 83 m2 aluminized polyimide solar sail to propel a spacecraft to encounter a near-Earth asteroids (NEA). The planned target, subject to change, is near-Earth object 1991 VG.
Additional Videos on LightSail 2
Here is a look inside the spacecraft, the development lab and the engineering staff -
Here is an interesting test and demonstration of the unfurling of the light sail -
Some Additional Resources for Launch Enthusiasts
Weather outlook is good. Has improved to 80% favorable.
Why Space Exploration?
For some additional insights into why we, as humanity, look beyond Earth, check out these inspiring videos and some of the references below -
Epilogue
We are fortunate there are scientists, engineers and technicians, looking beyond Earth to find solutions to the man-made problems, in which we simmer and stew. Carl Sagan famously said many decades ago — ”We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.” The situation perhaps has not changed much, at least for one segment of our society. But we need to keep working — to improve our knowledge and skills about science, both ours and those of the generations to come.
Science is exciting. Science is inspiring. Science is liberating. Three cheers for Science.
And Bon voyage LightSail 2 — May the Force be with You.
P.S. I hope some of you get to watch the launch in Florida.
P.S I published this diary yesterday. But I am re-publishing it today as a liveblog diary. I have added and edited a good bit of content and also added more info and tweets in the comments section. Hopefully, we will have a lively discussion of the launch and on the other space technology matters.
Further Reading
- STP-2 Press Kit — www.spacex.com/…
- LightSail 2 Press Kit — www.planetary.org/...
- NASA’s SET Mission to Study Satellite Protection Is Ready for Launch — www.nasa.gov/…
- What Is an Atomic Clock? — www.nasa.gov/…
- E-TBEx: Enhanced Tandem Beacon Experiment — www.nasa.gov/…
- LightSail — www.planetary.org/…
- What is Solar Sailing? — www.planetary.org/…
- Solar sail — en.wikipedia.org/…
- Bill Nye the Science Guy talks “solar sailing” and the new space race — www.digitaltrends.com/...
- LightSail Media Gallery — www.planetary.org/…
- IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) — earth.esa.int/...
- SpaceX Falcon User’s Guide — www.spacex.com/…
- SpaceX Falcon Heavy Launch of Arabsat-6A, with Triple Booster Landing - Liveblog — www.dailykos.com/…
- Why Go To Mars? And other Planets and Moons — www.dailykos.com/...
Updates, Monday June 24