Topic 5 Intro to Space/Orbits Enabling Objectives 5.1 DESCRIBE space operations.

1. Topic 5 Intro to Space/Orbits Enabling Objectives 5.1 DESCRIBE space operations. 5.2 DESCRIBE the Space Cadre. 5.3 IDENTIFY the categories of space missions. 5.4 DESCRIBE the space command organization. 5.5 DESCRIBE the concept of orbit. 5.6 DESCRIBE Kepler’s and Newton’s Laws. 5.7 IDENTIFY the classical orbital elements. 5.8 DESCRIBE ground tracks (Map Projection) and effects of orbit types. 5.9 DESCRIBE launch windows and the effects of launch latitude. 5.10 DESCRIBE spacecraft limitations. 5.11 DESCRIBE benefits and costs of satellite-based communications.

2. COMMERCIAL The SATCOM Mission Provide timely access to information and dissemination of decisions to globally deployed military forces FLTSATCOM UHF Follow-On DSCS MILSTAR

3. SATCOMSatellite Communications allow Information Superiority

5. The Space Cadre “We need space professionals in all services and agencies … to exploit space effectively in the interests of national security.Development of a space cadre is one of our top agenda items for national security space programs in 2004” -- Under Secretary of the AF Peter B. TeetsReport to Congress, 12MAR03

7. Is not a community It is a distinct body of space expertise horizontally integrated within the Navy and Marine Corps active duty, reserves, and civilian employee communities Navy URL, IP, AEDO, Intel, NSG USMC MOS 9666 and 9933 Naval Reserve Program 18 primary reserve pool Working to complete identification of civilians and enlisted Navy and Marine Corps space professionals have been recognized since the 1980’s, when the sub-specialty codes were established. However, recognition for focused management in response to SECDEF direction has resulted in the establishment of the Navy Space Cadre Advisor. Naval Space Cadre

8. Unique Aspects of Space • Space systems must be fully operational from the get go • They are either up and running or inoperable • On orbit Spare/Residual satellites are the “National Guard and Reserve Forces” for satellite systems • No ability to “surge” • Finite service life • Launched satellite is a “dead man walking” • No SLEP or hardware mods available after launch –only what’s built in • No ability to inspect/service satellites – sustainment needs difficult to predict • Typically, all satellites in a constellation have to be operational for the system to be operational • The satellite operators greatest fear Gaps in Con stel la tions

9. Categories of Space Missions • We spend over $100B worldwide each year on space systems • Since 1999 over half of that money has gone to non-military systems • We exploit the “high ground” of space to more efficiently: • Communicate • Observe • Navigate • NASA spends about $15B per year to scientifically explore our world

10. Satellite Communications • Majority of money for space projects is used for communications • The Sputnik spacecraft was basically a communications satellite

11. Ikonos satellite, 1 m resolution www.spaceimaging.com Quickbird satellite, 0.6 m resolution www.digitalglobe.com US: Fig. 1-13 Russian Spin 2 satellite, 2 m resolution www.terraserver.microsoft.com Satellite Observation • Observe the Earth and heavens from a distance (remote sensing) • Monitor the Earth’s environment • Observe the heavens: Hubble and Chandra • Watch the weather • Plan city growth • Detect enemy activity

12. GPS Block II-F satellite (Boeing) GPS Block II-R satellite (Lockheed) Satellite Navigation Systems like the GlobalPositioning System (GPS), the Russian Glonass system, and the proposed European Galileo system tell you where you are, what direction you’re headed, and how fast you’re going

14. National Space Organizations National Reconnaissance Office NRO National Geospatial and Intelligence Agency (Formerly NIMA) NGA National Security Agency NSA

15. USSTRATCOM (Space) Space and Missile Defense Command

16. COMSPAWAR (ADDU) Commander NETWARCOM 00 Operations N3 NCTAMS LANT NCTAMS PAC NAVSOC NMCI GNOC Naval Network Warfare Command ACNO IT / DDCIO FFC N6 Deputy Commander SES 02 Vice Commander 01 Chief of Staff O-6 03 Info Ops CNSG (ADDU) FORCEnet Deputy Dir Ops USMC Network Defense (NAVCIRT) N31 Fleet C5ISR Modernization N32 Enterprise Operations (GNOSC) N33 Fleet Support N34 Enterprise Architecture N6 Requirements N8 Enterprise Management N5 Information Ops Global SA Human Capital Management N1 Logistics Management N4 Innovation & Experimentation N9 Flag Special Assistants Office of the DAA FORCEnet Coordinator Enterprise Transformation Group Comptroller Special Assistants JAG PAO IO KM Safety Security IG EOA SEA HP Det Career Counselor

17. Space Division(N8 Directorate) JCIDS Space Wargames (Schriever and Thor's Hammer, etc): Space Control: Maritime Domain Awareness (MDA): Modeling and Simulation Sea Trial: Space Situational Awareness (SSA) AF SC Interface: Space Control Maritime Domain Awareness (MDA) Space Training and Test Range AF SC Interface: Ground Terminals: Maritime Domain Awareness (MDA): Naval-NRO Coordination Group (NNCG):

18. Civil Space Organizations

19. Orbital MotionGravity and the Concept of Freefall • So what keeps a spacecraft in orbit? • Consider a thrown ball • If thrown hard enough, we can use the Earth’s curvature to keep the ball flying • The Earth curves or drops about 5m for every 8km • Gravity causes the ball to “fall” toward the center of the Earth • We can use this feature to launch the ball into orbit

20. Freefall and Orbits • If we throw hard (fast) enough, our ball will go out faster than it falls, so it never hits the ground • If we throw it pretty fast, it’s an ICBM (Intercontinental Ballistic Missile) • If we throw it just fast enough, it’s in a circular orbit • If we throw it faster, the orbit is an ellipse • If we throw it real fast, it escapes the Earth on a parabola • If we throw it super fast, it escapes and goes to another planet on a hyperbola

22. Newton’s Laws • First Law: • A body remains at rest or in constant motion unless acted upon by external forces • If there were no gravity, our ball would go forever--and straight! • How about a rocket engine? • Second Law: • The time rate of change of an object’s momentum is equal to the applied force • Third Law: • For every action, there’s an equal and opposite reaction

23. Newton’s Universal Law of Gravitation Newton’s Universal Law of Gravitation: The force of gravity between 2 bodies is proportional to the product of the masses and inversely proportional to the square of the distance between them

24. Gravity: Magnitude • So what is this thing called gravity? • Who Knows? • BUT, it is everywhere and all powerful! • Let’s look at the Earth-Moon system: • How big is this? The Space Shuttle has about 7,000,000 lb. thrust at lift-off. The Earth-Moon gravity force is more than one trilliontimes as great as the Shuttle thrust!

26. US: Fig. 1-24 US: Fig. 1-25 Orbit TypesTrajectories and Orbits • A trajectory is the path an object follows through space • An orbit can be thought of as a fixed racetrack around a planet, where the size of the racetrack depends on the energy of the object in orbit • Orbit altitude and field of view dictate the swathwidth or coverage on the ground

28. Satellite Constellations - GEO Three satellites in GEO can give global coverage (with the exception of the polar regions, ±81°)

29. Satellite Constellations - MEO GPS uses a nominal constellation of 24 satellites (6 satellites in 4 orbital planes) to give full global coverage – this puts at least four satellites in view at any point simultaneously GPS MEO Constellation

30. Satellite Constellations - LEO • Iridium – First LEO SATCOM system • Nominal 66 satellites in six planes • As of 20 Jun ‘02, 80 in orbit (14 spares) • 780 km altitude • Provides worldwide cell phone coverage • DoD contract for 20,000 users Iridium Low Earth Orbit Constellation

31. Classical Orbital Elements The Two-body Equation of Motion Newton’s Universal Law of Gravitation gives us: • The solution is a conic trajectory • For satellites, the orbit is an ellipse or circle fixed in space • Satellites trade kinetic energy for potential energy (speed for altitude) as they travel around the orbit • We need six initial conditions to solve this equation • These are the Classical Orbital Elements: a, e, i, W, w, n

32. Classical Orbital Elements Orbit Size: Semi-major axis a Orbit Twist: Ascending node location Ω Orbit Shape: Eccentricity e Orbit Rotation: Perigee location ω Orbit Tilt: Inclination i Satellite Position: True anomaly υ

34. Orbital Period - P • The orbit’s period – how long the satellite takes to go around once – is proportional to the orbit size • For the Space Shuttle, the period is about 90 minutes. It orbits the Earth about 16 times each day! • For a communications satellite--which provide HBO, MCI, AT&T,etc., the period is exactly 23 hours, 56 minutes, and 4 seconds. Why? [Sidereal vs. Solar Day]

35. Shape: Eccentricity (e) Circle e = 0.0 Ellipse e = 0.0 to 1.0 Parabola e = 1.0 Hyperbola e > 1.0

36. Inclination h i Angular momentum vector Orbital Tilt K Equatorial Plane Ascending Node

37. Orientation: Right Ascension of the Ascending Node () We measure how an orbit is twisted by locating its ascending node relative to the vernal equinox direction (in the equatorial plane) Vernal Equinox Direction (Originally pointed to the constellation Aries, the Ram) Equatorial Plane Ascending Node  Right Ascension of the Ascending Node

38. Argument of Perigee  Ascending Node Perigee (Point Closest to the Earth) Location: Argument of Perigee () We locate perigee relative to the ascending node (in the orbit plane) Equatorial Plane

39.  True Anomaly Location: True Anomaly () Finally, we locate the satellite relative to perigee, (in the orbit plane) Equatorial Plane Perigee (Point Closest to the Earth)

40. Ground Trace ~ 15o per hour Ground Tracks - Map Projection A ground track is the projection of a satellite’s orbit onto the Earth’s surface Certain orbits will have a westward shifting ground track due to the Earth's rotation

41. Earth Rotation Adding Earth’s rotation yields a ground track that shifts west Using ground tracks, we can determine period, inclination, and estimate eccentricity and argument of perigee

42. Period Effects on Ground Tracks Earth rotates at 15 deg/hour--period can be estimated from multiple paths

43. Launch Site Launch Windows Desired Orbit Plane

44. Inclination and Launch Latitude Cannot launch into an inclination less than a launch site’s latitude We must do a plane change maneuver to get to the equatorial plane! Launch Due East Launch Southeast Launch Northeast

45. Spacecraft Limitations • Payload limited by weight and size • Expendables are finite • Fuel for positioning • Battery & solar cell degradation • Repairing very difficult • Redundant systems • On-orbit spares • Hostile environment

46. SATCOM … the Benefits • The ultimate high ground • Persistence • No large infrastructure at deployed locations • Enables JV-2010/2020 • Real time transmission of voice and data • Data relay • Security • Flexibility • Support to mobile forces

47. SATCOM – More Benefits • Real time transmission of voice and data • Data relay • No need for long land links, approvals or tariffs • No hostile territory or difficult terrain issues • Security • Encryption devices on terminals and spacecraft • Flexibility • Near-global coverage • Interlinking between frequency bands • Low Probability of Detection (LPD) • Support to mobile forces • High-capacity comm over wide areas • No large comm infrastructure required

48. SATCOM … the Costs • Expensive • Complex • Subject to international rules • Single point failure

50. Space Frequencies 1 m 10 cm 1 cm 1 mm UHF SHF EHF 1 2 4 8 12 18 27 40 75 GHz Millimeter UHF L S C X Ku K Ka V Band Designations Atmosphere Absorption Ionospheric Reflection 300 MHz 3 GHz 30 GHz 300 GHz