SOLAR SAIL

Presented by DHEERAJ MURALI

M7 ,A 7316

Guided by

. . .Dr K A SHAFI

INTRODUCTION

400 years back Johannes Kepler proposed the idea

A spacecraft without an engine Pushed along directly by light from

the Sun - Reflects light off giant mirror like

sails ’ , Doesn t need fuel so weight is

reduced Keeps accelerating over almost unlimited distances

WORKING

Light is m ade up of packets of energy

know n as“ ”photons

Incident rays of sunlight reflect off

the solar sailat an angle

C hange in m om entum

pushes the sailforw ard

Two components of force

.i In the direction of the incident sunlight

.ii In a direction normal to the incidentrays

Components tangent to the sail surface cancel out Components normal to the surface add up to produce

the thrust normal to the sail surface = Reflected photons energy flux energy flux prior

, to the interaction but a different momentumvector

This altered momentum vector that gives the ship an accelerating force

WHY SOLAR SAILS ?

A Sail of 1 sq km are would only feel about 9 Newtons

Normal space shuttle main engine produceØ1.67 million N of force during liftoff Ø2.1 million N of thrust in a vacuum

How Solar sail is effectivei. no noticeable frictionii.space is very empty and clean so

there is plenty of roomiii.Continuous supply of energy

40 Au in 6 years

Distance from sun to Pluto= . 32 1 AU ’ NASA s New Horizon mission= 10 yrs

DISTANCE v/s TIME

SECTION A

Initial accelerationlow

Due to effect of gravity and low pressure increase

rate

SECTION A :- DETAILS

 In 100 days, a sail-propelled craft could reach 14,000 kilometres per hour

  In just three years, a solar sail could reach over 150,000 miles per hour.

At that speed, you could reach Pluto in less than five years

Far away from the Sun, the highly focused beams of lasers can be directed at the sails to boost them onto interstellar trajectories.

C O M PA R IT IV E S T U D Y

COMPONENTS

There are three components to a solar sail-powered spacecraft

i. Continuous force exerted by sunlightii.A large, ultrathin mirroriii.A separate launch vehicle

Ultra thin mirror :- large flat smooth sheets of very thin film, supported by ultra-lightweight structures

Side of film which faces the sun is coated with a highly reflective material

Some times reinforcement are also provided

vHeliogyro Plastic-film blades deployed from rollers

Film held out by centrifugal forces No mass advantage over a square sail Attractive because the method of deploying the sail is simpler than a Square sail.

SAIL DESIGNS

Spinning Disk Sail (Ring sails)a)Panels are attached to the edge of a rotating spacecrafthave slight gaps, about 1% - 5% of the total areab)Lines would connect the edges of sails

c) Weights in the middles of these lines would pull the sails taut

d)attractive sail design for large manned structures

S A IL D E P LO Y M E N T

COILED BOOM UNCOILED BOOM

BOOM STRUCTURE

Essential Qualitiesi. Lightweightii. Highly reflectiveiii.Tolerate extreme temperatures

Materialsa) Aluminiumb)Titaniumc)Nickeld)Silicon Monoxidee)Boron

SAIL MATERIALS

High reflectivity, low density, a reasonable melting point, and a very low vapour pressure

Doesn’t agglomerate due to formation of an oxide layer on the aluminium

Creep is a factor of concern Aluminium films of the minimum thickness

required for reflectivity mayi. Prove too weak to support the stresses

imposed during fabrication ii.Creep under load at elevated

temperatures.

A LU M IN IU M

Strengthened by adding a reinforcing , film of a stronger m ore refractory

.m aterial : , G ood reinforcing film features Strong

, Light and Easy to deposit N o need not for chem icalcom patibility

w ith alum inium , , M etals such as nickel m ay reflect w ell

and also provide reinforcem ent

Titanium and Nickel

Films of pure titanium from 150 to 2,000 nm thick were found to have strengths of 460 to 620 Npa

Titanium has enough strength and temperature tolerance to make it an attractive choice as a reinforcing film.`

Strength of nickel film exceeds 2,000 NPa at a thickness of 70 nanometers.

Nickel’s density is a disadvantage for use in sails

TIT A

NIU

MNIC K

EL

Silicon Monoxide and Boron

Satellite thermal control coatings Refractory, Low density, High strength in

extremely thin film form Reinforcing film material

Strength of 620 MPa Can be made as thin as 4 nanometres

SiO 2

BOR O

N

Nano satellite - or Cubesat Designed to test the

potential for solar sails in atmospheric braking

Used an ultra-thin and light polymer named CP1

Deployed in low-Earth orbit, about 650 km

Launched by Falcon-1 launch vehicle in August 2008

CASE STUDY : NANOSAIL-D

Immediately after ejection today, a timer started a three-day countdown.

On reaching zero count , all four booms will spring out from the small satellite, and within five seconds the sail will be fully extended

Final size of 100 square foot (10 square meter) sail-span.

Solar weather stations Monitoring the

geomagnetic storms Launching small

satellites Remote sensing Probes to end of Milky

way Search for extra

terrestrial life

APPLICATIONS

Merits and Demerits

Longer distance can be covered Requires no fuel Faster than a chemical rocket

Don't work well in low Earth orbit below about 800 km altitude due to erosion or air drag. 

Sails have to be physically large Payload size is often small. Difficult to carry manned missions

DEMERI

TS

MERIT

S

Solar sailtechnology w illeventually play a key -role in long distance N A S A  m issions

Exploration of space is sim ilar to the tale of the" ," - Tortoise and the Hare with rocket propelled

.spacecraft being the hare , - in this race the rocket propelled spacecraft w ill

, quickly jum p out m oving quickly tow ard its.destination

, O n the other hand a rocket less spacecraft pow ered by a solar sailw ould begin its

, journey at a slow but steady pace gradually picking up speed

CONCLUSIONS

NanoSail-D: A solar sail demonstration mission by Les Johnson, MarkWhorton , AndyHeaton , RobinPinson , GregLaue , CharlesAdams Acta Astronautica 68 (2011) 571–575

Overview of Advanced Space Propulsion via Solar Photon Sailing by Giovanni Vulpetti, International Academy of Astronautics

www.solarsails.org www.nasa.gov www.solarscience.co www.nanosail.org

R E F E R E N C E S