diff --git a/Julian.cpp b/Julian.cpp
index a2bc81b..e59175e 100644
--- a/Julian.cpp
+++ b/Julian.cpp
@@ -80,6 +80,9 @@ Julian::Julian(int year, int mon, int day, int hour, int min, double sec) {
     Initialize(year, mon, day, hour, min, sec);
 }
 
+/*
+ * comparison
+ */
 bool Julian::operator==(const Julian &date) const {
     return date_ == date.date_ ? true : false;
 }
@@ -104,6 +107,34 @@ bool Julian::operator<=(const Julian &date) const {
     return date_ <= date.date_ ? true : false;
 }
 
+/*
+ * assignment
+ */
+Julian& Julian::operator=(const Julian& b) {
+    date_ = b.date_;
+    return (*this);
+}
+
+Julian& Julian::operator=(const double b) {
+    date_ = b;
+    return (*this);
+}
+
+/*
+ * arithmetic
+ */
+Julian Julian::operator+(const Timespan& b) const {
+    Julian result(*this);
+    result.date_ += b.GetTotalDays();
+    return result;
+}
+
+Julian Julian::operator-(const Timespan& b) const {
+    Julian result(*this);
+    result.date_ -= b.GetTotalDays();
+    return result;
+}
+
 /*
  * create julian date from year and day of year
  */
diff --git a/Julian.h b/Julian.h
index 90c4a09..6d363ab 100644
--- a/Julian.h
+++ b/Julian.h
@@ -2,6 +2,7 @@
 #define JULIAN_H_
 
 #include "Globals.h"
+#include "Timespan.h"
 
 #include <ctime>
 
@@ -23,6 +24,11 @@ public:
     bool operator>=(const Julian &date) const;
     bool operator<=(const Julian &date) const;
 
+    Julian& operator=(const Julian& b);
+Julian& operator=(const double b);
+Julian operator+(const Timespan& b) const;
+Julian operator-(const Timespan& b) const;
+
     ~Julian() {
     };
 
diff --git a/Rewrite.vcxproj b/Rewrite.vcxproj
index 2659507..6fafd62 100644
--- a/Rewrite.vcxproj
+++ b/Rewrite.vcxproj
@@ -81,6 +81,7 @@
     <ClCompile Include="main.cpp" />
     <ClCompile Include="Observer.cpp" />
     <ClCompile Include="SGDP4.cpp" />
+    <ClCompile Include="Timespan.cpp" />
     <ClCompile Include="Tle.cpp" />
     <ClCompile Include="Vector.cpp" />
   </ItemGroup>
@@ -92,6 +93,7 @@
     <ClInclude Include="Observer.h" />
     <ClInclude Include="SatelliteException.h" />
     <ClInclude Include="SGDP4.h" />
+    <ClInclude Include="Timespan.h" />
     <ClInclude Include="Tle.h" />
     <ClInclude Include="Vector.h" />
   </ItemGroup>
diff --git a/Rewrite.vcxproj.filters b/Rewrite.vcxproj.filters
index 6a3137c..1b568a0 100644
--- a/Rewrite.vcxproj.filters
+++ b/Rewrite.vcxproj.filters
@@ -42,6 +42,9 @@
     <ClCompile Include="Eci.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="Timespan.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Coord.h">
@@ -71,5 +74,8 @@
     <ClInclude Include="Eci.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="Timespan.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/Timespan.cpp b/Timespan.cpp
new file mode 100644
index 0000000..023ff76
--- /dev/null
+++ b/Timespan.cpp
@@ -0,0 +1,118 @@
+#include "Timespan.h"
+
+#include "Globals.h"
+
+Timespan::Timespan(void) {
+}
+
+Timespan::Timespan(const double time_span) {
+}
+
+Timespan::Timespan(const Timespan& b) {
+
+    time_span_ = b.time_span_;
+}
+
+Timespan::~Timespan(void) {
+}
+
+Timespan& Timespan::operator =(const Timespan& b) {
+
+    if (this != &b) {
+        time_span_ = b.time_span_;
+
+    }
+    return (*this);
+}
+
+Timespan Timespan::operator +(const Timespan& b) const {
+
+    Timespan result(*this);
+    result.time_span_ += b.GetTotalDays();
+    return result;
+}
+
+Timespan Timespan::operator -(const Timespan& b) const {
+
+    Timespan result(*this);
+    result.time_span_ -= b.GetTotalDays();
+    return result;
+}
+
+const Timespan & Timespan::operator+=(const Timespan& b) {
+
+    time_span_ += b.time_span_;
+    return (*this);
+}
+
+const Timespan & Timespan::operator-=(const Timespan& b) {
+
+    time_span_ -= b.time_span_;
+    return (*this);
+}
+
+Timespan Timespan::operator +() const {
+
+    Timespan result(*this);
+    result.time_span_ = +result.time_span_;
+    return result;
+}
+
+Timespan Timespan::operator -() const {
+
+    Timespan result(*this);
+    result.time_span_ = -result.time_span_;
+    return result;
+}
+
+bool Timespan::operator ==(const Timespan& b) const {
+
+    if (time_span_ == b.time_span_)
+        return true;
+    else
+        return false;
+}
+
+bool Timespan::operator !=(const Timespan& b) const {
+
+    if (time_span_ == b.time_span_)
+        return false;
+    else
+        return true;
+}
+
+bool Timespan::operator>(const Timespan& b) const {
+
+    if (time_span_ > b.time_span_)
+        return true;
+    else
+        return false;
+}
+
+bool Timespan::operator<(const Timespan& b) const {
+
+    if (time_span_ < b.time_span_)
+        return true;
+    else
+        return false;
+}
+
+bool Timespan::operator >=(const Timespan& b) const {
+
+    if (time_span_ >= b.time_span_)
+        return true;
+    else
+        return false;
+}
+
+bool Timespan::operator <=(const Timespan & b) const {
+
+    if (time_span_ <= b.time_span_)
+        return true;
+    else
+        return false;
+}
+
+double Timespan::GetTotalDays() const{
+    return time_span_ / Globals::MIN_PER_DAY();
+}
\ No newline at end of file
diff --git a/Timespan.h b/Timespan.h
new file mode 100644
index 0000000..236bab4
--- /dev/null
+++ b/Timespan.h
@@ -0,0 +1,38 @@
+#ifndef TIMESPAN_H_
+#define TIMESPAN_H_
+
+class Timespan {
+public:
+    Timespan(void);
+    Timespan(const double time_span);
+    Timespan(const Timespan& b);
+    virtual ~Timespan(void);
+
+    double GetTotalDays() const;
+
+    /*
+     * overloaded operators
+     */
+    Timespan & operator=(const Timespan& b);
+    Timespan operator+(const Timespan& b) const;
+    Timespan operator-(const Timespan& b) const;
+    Timespan operator+() const;
+    Timespan operator-() const;
+    const Timespan & operator+=(const Timespan& b);
+    const Timespan & operator-=(const Timespan& b);
+    bool operator==(const Timespan& b) const;
+    bool operator!=(const Timespan& b) const;
+    bool operator>(const Timespan& b) const;
+    bool operator<(const Timespan& b) const;
+    bool operator>=(const Timespan& b) const;
+    bool operator<=(const Timespan& b) const;
+
+private:
+    /*
+     * stores value in minutes
+     */
+    double time_span_;
+};
+
+#endif
+